By Galen

Translated by Arthur John Brock

1. It has been made clear in the preceding discussion that nutrition
occurs by an alteration or assimilation of that which nourishes to
that which receives nourishment, and that there exists in every part
of the animal a faculty which in view of its activity we call, in
general terms, alterative, or, more specifically, assimilative and
nutritive. It was also shown that a sufficient supply of the matter
which the part being nourished makes into nutriment for itself is
ensured by virtue of another faculty which naturally attracts its
proper juice [humour] that juice is proper to each part which is adapted
for assimilation, and that the faculty which attracts the juice is
called, by reason of its activity, attractive or epispastic. It has
also been shown that assimilation is preceded by adhesion, and this,
again, by presentation, the latter stage being, as one might say,
the end or goal of the activity corresponding to the attractive faculty.
For the actual bringing up of nutriment from the veins into each of
the parts takes place through the activation of the attractive faculty,
whilst to have been finally brought up and presented to the part is
the actual end for which we desired such an activity; it is attracted
in order that it may be presented. After this, considerable time is
needed for the nutrition of the animal; whilst a thing may be even
rapidly attracted, on the other hand to become adherent, altered,
and entirely assimilated to the part which is being nourished and
to become a part of it, cannot take place suddenly, but requires a
considerable amount of time. But if the nutritive juice, so presented,
does not remain in the part, but withdraws to another one, and keeps
flowing away, and constantly changing and shifting its position, neither
adhesion nor complete assimilation will take place in any of them.
Here too, then, the [animal's] nature has need of some other faculty
for ensuring a prolonged stay of the presented juice at the part,
and this not a faculty which comes in from somewhere outside but one
which is resident in the part which is to be nourished. This faculty,
again, in view of its activity our predecessors were obliged to call
retentive. 

Thus our argument has clearly shown the necessity for the genesis
of such a faculty, and whoever has an appreciation of logical sequence
must be firmly persuaded from what we have said that, if it be laid
down and proved by previous demonstration that Nature is artistic
and solicitous for the animal's welfare, it necessarily follows that
she must also possess a faculty of this kind. 

2. Since, however, it is not our habit to employ this kind of demonstration
alone, but to add thereto cogent and compelling proofs drawn from
obvious facts, we will also proceed to the latter kind in the present
instance: we will demonstrate that in certain parts of the body the
retentive faculty is so obvious that its operation can be actually
recognised by the senses, whilst in other parts it is less obvious
to the senses, but is capable even here of being detected by the argument.

Let us begin our exposition, then, by first dealing systematically
for a while with certain definite parts of the body, in reference
to which we may accurately test and enquire what sort of thing the
retentive faculty is. 

Now, could one begin the enquiry in any better way than with the largest
and hollowest organs? Personally I do not think one could. It is to
be expected that in these, owing to their size, the activities will
show quite clearly, whereas with respect to the small organs, even
if they possess a strong faculty of this kind, its activation will
not at once be recognisable to sense. 

Now those parts of the animal which are especially hollow and large
are the stomach and the organ which is called the womb or uterus.
What prevents us, then, from taking up these first and considering
their activities, conducting the enquiry on our own persons in regard
to those activities which are obvious without dissection, and, in
the case of those which are more obscure, dissecting animals which
are near to man; not that even animals unlike him will not show, in
a general way, the faculty in question, but because in this manner
we may find out at once what is common to all and what is peculiar
to ourselves, and so may become more resourceful in the diagnosis
and treatment of disease. 

Now it is impossible to speak of both organs at once, so we shall
deal with each in turn, beginning with the one which is capable of
demonstrating the retentive faculty most plainly. For the stomach
retains the food until it has quite digested it, and the uterus retains
the embryo until it brings it to completion, but the time taken for
the completion of the embryo is many times more than that for the
digestion of food. 

3. We may expect, then, to detect the retentive faculty in the uterus
more clearly in proportion to the longer duration of its activity
as compared with that of the stomach. For, as we know, it takes nine
months in most women for the foetus to attain maturity in the womb,
this organ having its neck quite closed, and entirely surrounding
the embryo together with the chorion. Further, it is the utility of
the function which determines the closure of the os and the stay of
the foetus in the uterus. For it is not casually nor without reason
that Nature has made the uterus capable of contracting upon, and of
retaining the embryo, but in order that the latter may arrive at a
proper size. When, therefore, the object for which the uterus brought
its retentive faculty into play has been fulfilled, it then stops
this faculty and brings it back to a state of rest, and employs instead
of it another faculty hitherto quiescent- the propulsive faculty.
In this case again the quiescent and active states are both determined
by utility; when this calls, there is activity; when it does not,
there is rest. 

Here, then, once more, we must observe well the Art [artistic tendency]
of Nature- how she has not merely placed in each organ the capabilities
of useful activities, but has also fore-ordained the times both of
rest and movement. For everything connected with the pregnancy proceeds
properly, the eliminative faculty remains quiescent as though it did
not exist, but if anything goes wrong in connection either with the
chorion or any of the other membranes or with the foetus itself, and
its completion is entirely despaired of, then the uterus no longer
awaits the nine-months period, but the retentive faculty forthwith
ceases and allows the heretofore inoperative faculty to come into
action. Now it is that something is done- in fact, useful work effected-
by the eliminative or propulsive faculty (for so it, too, has been
called, receiving, like the rest,its names from the corresponding
activities). 

Further, our theory can, I think, demonstrate both together; for seeing
that they succeed each other, and that the one keeps giving place
to the other according as utility demands, it seems not unreasonable
to accept a common demonstration also for both. Thus it is the work
of the retentive faculty to make the uterus contract upon the foetus
at every point, so that, naturally enough, when the midwives palpate
it, the os is found to be closed, whilst the pregnant women themselves,
during the first days- and particularly on that on which conception
takes place- experience a sensation as if the uterus were moving and
contracting upon itself. Now, if both of these things occur- if the
os closes apart from inflammation or any other disease, and if this
is accompanied by a feeling of movement in the uterus- then the women
believe that they have received the semen which comes from the male,
and that they are retaining it. 

Now we are not inventing this for ourselves: one may say the statement
is based on prolonged experience of those who occupy themselves with
such matters. Thus Herophilus does not hesitate to state in his writings
that up to the time of labour the os uteri will not admit so much
as the tip of a probe, that it no longer opens to the slightest degree
if pregnancy has begun- that, in fact, it dilates more widely at the
times of the menstrual flow. With him are in agreement all the others
who have applied themselves to this subject; and particularly Hippocrates,
who was the first of all physicians and philosophers to declare that
the os uteri closes during pregnancy and inflammation, albeit in pregnancy
it does not depart from its own nature, whilst in inflammation it
becomes hard. 

In the case of the opposite (the eliminative) faculty, the os opens,
whilst the whole fundus approaches as near as possible to the os,
expelling the embryo as it does so; and along with the fundus the
contiguous parts- which form as it were a girdle round the whole organ-
cooperate in the work; they squeeze upon the embryo and propel it
bodily outwards. And, in many women who exercise such a faculty immoderately,
violent pains cause forcible prolapse of the whole womb; here almost
the same thing happens as frequently occurs in wresting-bouts and
struggles, when in our eagerness to overturn and throw others we are
ourselves upset along with them; for similarly when the uterus is
forcing the embryo forward it sometimes becomes entirely prolapsed,
and particularly when the ligaments connecting it with the spine happen
to be naturally lax. 

A wonderful device of Nature's also is this- that, when the foetus
is alive, the os uteri is closed with perfect accuracy, but if it
dies, the os at once opens up to the extent which is necessary for
the foetus to make its exit. The midwife, however, does not make the
parturient woman get up at once and sit down on the [obstetric] chair,
but she begins by palpating the os as it gradually dilates, and the
first thing she says is that it has dilated "enough to admit the little
finger," then that "it is bigger now," and as we make enquiries from
time to time, she answers that the size of the dilatation is increasing.
And when it is sufficient to allow of the transit of the foetus, she
then makes the patient get up from her bed and sit on the chair, and
bids her make every effort to expel the child. Now, this additional
work which the patient does of herself is no longer the work of the
uterus but of the epigastric muscles, which also help us in defaecation
and micturition. 

4. Thus the two faculties are clearly to be seen in the case of the
uterus; in the case of the stomach they appear as follows:- Firstly
in the condition of gurgling, which physicians are persuaded, and
with reason, to be a symptom of weakness of the stomach; for sometimes
when the very smallest quantity of food has been ingested this does
not occur, owing to the fact that the stomach is contracting accurately
upon the food and constricting it at every point; sometimes when the
stomach is full the gurglings yet make themselves heard as though
it were empty. For if it be in a natural condition, employing its
contractile faculty in the ordinary way, then, even if its contents
be very small, it grasps the whole of them and does not leave any
empty space. When it is weak, however, being unable to lay hold of
its contents accurately, it produces a certain amount of vacant space,
and amount of vacant space, and allows the liquid contents to flow
about in different directions in accordance with its changes of shape,
and so to produce gurglings. 

Thus those who are troubled with this symptom expect, with good reason,
that they will also be unable to digest adequately; proper digestion
cannot take place in a weak stomach. In such people also, the mass
of food may be plainly seen to remain an abnormally long time in the
stomach, as would be natural if their digestion were slow. Indeed,
the chief way in which these people will surprise one is in the length
of time that not food alone but even fluids will remain in their stomachs.
Now, the actual cause of this is not, as one would imagine, that the
lower outlet of the stomach, being fairly narrow, will allow nothing
to pass before being reduced to a fine state of division. There are
a great many people who frequently swallow large quantities of big
fruit-stones; one person who was holding a gold ring in his mouth,
inadvertently swallowed it; another swallowed a coin, and various
people have swallowed various hard and indigestible objects; yet all
these people easily passed by the bowel what they had swallowed, without
there being any subsequent symptoms. Now surely if narrowness of the
gastric outlet were the cause of untriturated food remaining for an
abnormally long time, none of these articles I have mentioned would
ever have escaped. Furthermore, the fact that it is liquids which
remain longest in these people's stomachs is sufficient to put the
idea of narrowness of the outlet out of court. For, supposing a rapid
descent were dependent upon emulsification, then soups, milk, and
barley-emulsion would at once pass along in every case. But as a matter
of fact this is not so. For in people who are extremely asthenic it
is just these fluids which remain undigested, which accumulate and
produce gurglings, and which oppress and overload the stomach, whereas
in strong persons not merely do none of these things happen, but even
a large quantity of bread or meat passes rapidly down. 

And it is not only because the stomach is distended and loaded and
because the fluid runs from one part of it to another accompanied
by gurglings- it is not only for these reasons that one would judge
that there was an unduly long continuance of the food in it, in those
people who are so disposed, but also from the vomiting. Thus, there
are some who vomit up every particle of what they have eaten, not
after three or four hours, but actually in the middle of the night,
a lengthy period having elapsed since their meal. 

Suppose you fill any animal whatsoever with liquid food- an experiment
I have often carried out in pigs, to whom I give a sort of mess of
wheaten flour and water, there after cutting them open after three
or four hours; if you will do this yourself, you will find the food
still in the stomach. For it is not chylification which determines
the length of its stay here- since this can also be effected outside
the stomach; the determining factor is digestion which is a different
thing from chylification, as are blood-production and nutrition. For,
just as it has been shown that these two processes depend upon a change
of qualities, similarly also the digestion of food in the stomach
involves a transmutation of it into the quality proper to that which
is receiving nourishment. Then, when it is completely digested, the
lower outlet opens and the food is quickly ejected through it, even
if there should be amongst it abundance of stones, bones, grape-pips,
or other things which cannot be reduced to chyle. And you may observe
this yourself in an animal, if you will try to hit upon the time at
which the descent of food from the stomach takes place. But even if
you should fail to discover the time, and nothing was yet passing
down, and the food was still undergoing digestion in the stomach,
still even then you would find dissection not without its uses. You
will observe, as we have just said, that the pylorus is accurately
closed, and that the whole stomach is in a state of contraction upon
the food very much as the womb contracts upon the foetus. For it is
never possible to find a vacant space in the uterus, the stomach,
or in either of the two bladders- that is, either in that called bile-receiving
or in the other; whether their contents be abundant or scanty, their
cavities are seen to be replete and full, owing to the fact that their
coats contract constantly upon the contents- so long, as least, as
the animal is in a natural condition. 

Now Erasistratus for some reason declares that it is the contractions
of the stomach which are the cause of everything- that is to say,
of the softening of the food, the removal of waste matter, and the
absorption of the food when chylified [emulsified]. 

Now I have personally, on countless occasions, divided the peritoneum
of a still living animal and have always found all the intestines
contracting peristaltically upon their contents. The condition of
the stomach, however, is found less simple; as regards the substances
freshly swallowed, it had grasped these accurately both above and
below, in fact at every point, and was as devoid of movement as though
it had grown round and become united with the food. At the same time
I found the pylorus persistently closed and accurately shut, like
the os uteri on the foetus. 

In the cases, however, where digestion had been completed the pylorus
had opened, and the stomach was undergoing peristaltic movements,
similar to those of the intestines. 

5. Thus all these facts agree that the stomach, uterus, and bladders
possess certain inborn faculties which are retentive of their own
proper qualities and eliminative of those that are foreign. For it
has been already shown that the bladder by the liver draws bile into
itself, while it is also quite obvious that it eliminates this daily
into the stomach. Now, of course, if the eliminative were to succeed
the attractive faculty and there were not a retentive faculty between
the two, there would be found, on every occasion that animals were
dissected, an equal quantity of bile in the gall-bladder. This however,
we do not find. For the bladder is sometimes observed to be very full,
sometimes quite empty, while at other times you find in it various
intermediate degrees of fulness, just as is the case with the other
bladder- that which receives the urine; for even without resorting
to anatomy we may observe that the urinary bladder continues to collect
urine up to the time that it becomes uncomfortable through the increasing
quantity of urine or the irritation caused by its acidity- the presumption
thus being that here, too, there is a retentive faculty.

Similarly, too, the stomach, when, as often happens, it is irritated
by acidity, gets rid of the food, although still undigested, earlier
than proper; or again, when oppressed by the quantity of its contents,
or disordered from the co-existence of both conditions, it is seized
with diarrhoea. Vomiting also is an affection of the upper [part of
the] stomach analogous to diarrhoea, and it occurs when the stomach
is overloaded or is unable to stand the quality of the food or surplus
substances which it contains. Thus, when such a condition develops
in the lower parts of the stomach, while the parts about the inlet
are normal, it ends in diarrhoea, whereas if this condition is in
the upper stomach, the lower parts being normal, it ends in vomiting.

6. This may often be clearly in those who are disinclined for food;
when obliged to eat, they have not the strength to swallow, and, even
if they force themselves to do so, they cannot retain the food, but
at vomit it up. And those especially who have a dislike to some particular
kind of food, sometimes take it under compulsion, and then promptly
bring it up; or, if they force themselves to keep it down, they are
nauseated and feel their stomach turned up, and endeavouring to relieve
itself of its discomfort. 

Thus, as was said at the beginning, all the observed facts testify
that there must exist in almost all parts of the animal a certain
inclination towards, or, so to speak, an appetite for their own special
quality, and an aversion to, or, as it were, a hatred of the foreign
quality. And it is natural that when they feel an inclination they
should attract, and that when they feel aversion they should expel.

From these facts, then, again, both the attractive and the propulsive
faculties have been demonstrated to exist in everything.

But if there be an inclination or attraction, there will also be some
benefit derived; for no existing thing attracts anything else for
the mere sake of attracting, but in order to benefit by what is acquired
by the attraction. And of course it cannot benefit by it if it cannot
retain it. Herein, then, again, the retentive faculty is shown to
have its necessary origin: for the stomach obviously inclines towards
its own proper qualities and turns away from those that are foreign
to it. 

But if it aims at and attracts its food and benefits by it while retaining
and contracting upon it, we may also expect that there will be some
termination to the benefit received, and that thereafter will come
the time for the exercise of the eliminative faculty. 

7. But if the stomach both retains and benefits by its food, then
it employs it for the end for which it [the stomach] naturally exists.
And it exists to partake of that which is of a quality befitting and
proper to it. Thus it attracts all the most useful parts of the food
in a vaporous and finely divided condition, storing this up in its
own coats, and applying it to them. And when it is sufficiently full
it puts away from it, as one might something troublesome, the rest
of the food, this having itself meanwhile obtained some profit from
its association with the stomach. For it is impossible for two bodies
which are adapted for acting and being acted upon to come together
without either both acting or being acted upon, or else one acting
and the other being acted upon. For if their forces are equal they
will act and be acted upon equally, and if the one be much superior
in strength, it will exert its activity upon its passive neighbour;
thus, while producing a great and appreciable effect, it will itself
be acted upon either little or not at all. But it is herein also that
the main difference lies between nourishing food and a deleterious
drug; the latter masters the forces of the body, whereas the former
is mastered by them. 

There cannot, then, be food which is suited for the animal which is
not also correspondingly subdued by the qualities existing in the
animal. And to be subdued means to undergo alteration. Now, some parts
are stronger in power and others weaker; therefore, while all will
subdue the nutriment which is proper to the animal, they will not
all do so equally. Thus the stomach will subdue and alter its food,
but not to the same extent as will the liver, veins, arteries, and
heart. 

We must therefore observe to what extent it does alter it. The alteration
is more than that which occurs in the mouth, but less than that in
the liver and veins. For the latter alteration changes the nutriment
into the substance of blood, whereas that in the mouth obviously changes
it into a new form, but certainly does not completely transmute it.
This you may discover in the food which is left in the intervals between
the teeth, and which remains there all night; the bread is not exactly
bread, nor the meat meat, for they have a smell similar to that of
the animal's mouth, and have been disintegrated and dissolved, and
have had the qualities of the animal's flesh impressed upon them.
And you may observe the extent of the alteration which occurs to food
in the mouth if you will chew some corn and then apply it to an unripe
[undigested] boil: you will see it rapidly transmuting- in fact entirely
digesting- the boil, though it cannot do anything of the kind if you
mix it with water. And do not let this surprise you; this phlegm [saliva]
in the mouth is also a cure for lichens; it even rapidly destroys
scorpions; while, as regards the animals which emit venom, some it
kills at once, and others after an interval; to all of them in any
case it does great damage. Now, the masticated food is all, firstly,
soaked in and mixed up with this phlegm; and secondly, it is brought
into contact with the actual skin of the mouth; thus it undergoes
more change than the food which is wedged into the vacant spaces between
the teeth. 

But just as masticated food is more altered than the latter kind,
so is food which has been swallowed more altered than that which has
been merely masticated. Indeed, there is no comparison between these
two processes; we have only to consider what the stomach contains-
phlegm, bile, pneuma, [innate] heat, and, indeed the whole substance
of the stomach. And if one considers along with this the adjacent
viscera like a lot of burning hearths around a great cauldron- to
the right the liver, to the left the spleen, the heart above, and
along with it the diaphragm (suspended and in a state of constant
movement), and the omentum sheltering them all- you may believe what
an extraordinary alteration it is which occurs in the food taken into
the stomach. 

How could it easily become blood if it were not previously prepared
by means of a change of this kind? It has already been shown that
nothing is altered all at once from one quality to its opposite. How
then could bread, beef, beans, or any other food turn into blood if
they had not previously undergone some other alteration? And how could
the faeces be generated right away in the small intestine? For what
is there in this organ more potent in producing alteration than the
factors in the stomach? Is it the number of the coats, or the way
it is surrounded by neighbouring viscera, or the time that the food
remains in it, or some kind of innate heat which it contains? Most
assuredly the intestines have the advantage of the stomach in none
of these respects. For what possible reason, then, will objectors
have it that bread may often remain a whole night in the stomach and
still preserve its original qualities, whereas when once it is projected
into the intestines, it straightway becomes ordure? For, if such a
long period of time is incapable of altering it, neither will the
short period be sufficient, or, if the latter is enough, surely the
longer time will be much more so! Well, then, can it be that, while
the nutriment does undergo an alteration in the stomach, this is a
different kind of alteration and one which is not dependent on the
nature of the organ which alters it? Or if it be an alteration of
this latter kind, yet one perhaps which is not proper to the body
of the animal? This is still more impossible. Digestion was shown
to be nothing else than an alteration to the quality proper to that
which is receiving nourishment. Since, then, this is what digestion
means and since the nutriment has been shown to take on in the stomach
a quality appropriate to the animal which is about to be nourished
by it, it has been demonstrated adequately that nutriment does undergo
digestion in the stomach. 

And Asclepiades is absurd when he states that the quality of the digested
food never shows itself either in eructations or in the vomited matter,
or on dissection. For of course the mere fact that the food smells
of the body shows that it has undergone gastric digestion. But this
man is so foolish that, when he hears the Ancients saying that the
food is converted in the stomach into something "good," he thinks
it proper to look out not for what is good in its possible effects,
but for what is good to the taste: this is like saying that apples
(for so one has to argue with him) become more apple-like [in flavour]
in the stomach, or honey more honey-like! 

Erasistratus, however, is still more foolish and absurd, either through
not perceiving in what sense the Ancients said that digestion is similar
to the process of boiling, or because he purposely confused himself
with sophistries. It is, he says, inconceivable that digestion, involving
as it does such trifling warmth, should be related to the boiling
process. This is as if we were to suppose that it was necessary to
put the fires of Etna under the stomach before it could manage to
alter the food; or else that, while it was capable of altering the
food, it did not do this by virtue of its innate heat, which of course
was moist, so that the word boil was used instead of bake.

What he ought to have done, if it was facts that he wished to dispute
about, was to have tried to show, first and foremost, that the food
is not transmuted or altered in quality by the stomach at all, and
secondly, if he could not be confident of this, he ought to have tried
to show that this alteration was not of any advantage to the animal.
If, again, he were unable even to make this misrepresentation, he
ought to have attempted to confute the postulate concerning the active
principles- to show, in fact, that the functions taking place in the
various parts do not depend on the way in which the Warm, Cold, Dry,
and Moist are mixed, but on some other factor. And if he had not the
audacity to misrepresent facts even so far as this, still he should
have tried at least to show that the Warm is not the most active of
all the principles which play a part in things governed by Nature.
But if he was unable to demonstrate this any more than any of the
previous propositions, then he ought not to have made himself ridiculous
by quarrelling uselessly with a mere name- as though Aristotle had
not clearly stated in the fourth book of his "Meteorology," as well
as in many other passages, in what way digestion can be said to be
allied to boiling, and also that the latter expression is not used
in its primitive or strict sense. 

But, as has been frequently said already, the one starting-point of
all this is a thorough-going enquiry into the question of the Warm,
Cold, Dry and Moist; this Aristotle carried out in the second of his
books "On Genesis and Destruction," where he shows that all the transmutations
and alterations throughout the body take place as a result of these
principles. Erasistratus, however, advanced nothing against these
or anything else that has been said above, but occupied himself merely
with the word "boiling." 

8. Thus, as regards digestion, even though he neglected everything
else, he did at least attempt to prove his point- namely, that digestion
in animals differs from boiling carried on outside; in regard to the
question of deglutition, however, he did not go even so far as this.
What are his words? 

"The stomach does not appear to exercise any traction." 
Now the fact is that the stomach possesses two coats, which certainly
exist for some purpose; they extend as far as the mouth, the internal
one remaining throughout similar to what it is in the stomach, and
the other one tending to become of a more fleshy nature in the gullet.
Now simple observation will testify that these coats have their fibres
inserted in contrary directions. And, although Erasistratus did not
attempt to say for what reason they are like this, I am going to do
so. 

The inner coat has its fibres straight, since it exists for the purpose
of traction. The outer coat has its fibres transverse, for the purpose
of peristalsis. In fact, the movements of each of the mobile organs
of the body depend on the setting of the fibres. Now please test this
assertion first in the muscles themselves; in these the fibres are
most distinct, and their movements visible owing to their vigour.
And after the muscles, pass to the physical organs, and you will see
that they all move in correspondence with their fibres. This is why
the fibres throughout the intestines are circular in both coats- they
only contract peristaltically, they do not exercise traction. The
stomach, again, has some of its fibres longitudinal for the purpose
of traction and the others transverse for the purpose of peristalsis.
For just as the movements in the muscles take place when each of the
fibres becomes tightened and drawn towards its origin, such also is
what happens in the stomach; when the transverse fibres tighten, the
breadth of the cavity contained by them becomes less; and when the
longitudinal fibres contract and draw in upon themselves, the length
must necessarily be curtailed. This curtailment of length, indeed,
is well seen in the act of swallowing: the larynx is seen to rise
upwards to exactly the same degree that the gullet is drawn downwards;
while, after the process of swallowing has been completed and the
gullet is released from tension, the larynx can be clearly seen to
again. This is because the inner coat of the stomach, which has the
longitudinal fibres and which also lines the gullet and the mouth,
extends to the interior of the larynx, and it is thus impossible for
it to be drawn down by the stomach without the larynx being involved
in the traction. 

Further, it will be found acknowledged in Erasistratus's own writings
that the circular fibres (by which the stomach as well as other parts
performs its contractions) do not curtail its length, but contract
and lessen its breadth. For he says that the stomach contracts peristaltically
round the food during the whole period of digestion. But if it contracts,
without in any way being diminished in length, this is because downward
traction of the gullet is not a property of the movement of circular
peristalsis. For what alone happens, as Erasistratus himself said,
is that when the upper parts contract the lower ones dilate. And everyone
knows that this can be plainly seen happening even in a dead man,
if water be poured down his throat; this symptom results from the
passage of matter through a narrow channel; it would be extraordinary
if the channel did not dilate when a mass was passing through it.
Obviously then the dilatation of the lower parts along with the contraction
of the upper is common both to dead bodies, when anything whatsoever
is passing through them, and to living ones, whether they contract
peristaltically round their contents or attract them. 

Curtailment of length, on the other hand, is peculiar to organs which
possess longitudinal fibres for the purpose of attraction. But the
gullet was shown to be pulled down; for otherwise it would not have
drawn upon the larynx. It is therefore clear that the stomach attracts
food by the gullet. 

Further, in vomiting, the mere passive conveyance of rejected matter
up to the mouth will certainly itself suffice to keep open those parts
of the oesophagus which are distended by the returned food; as it
occupies each part in front [above], it first dilates this, and of
course leaves the part behind [below] contracted. Thus, in this respect
at least, the condition of the gullet is precisely similar to what
it is in the act of swallowing. But there being no traction, the whole
length remains equal in such cases. 

And for this reason it is easier to swallow than to vomit, for deglutition
results the coats of the stomach being brought into action, the inner
one exerting a pull and the outer one helping by peristalsis and propulsion,
whereas emesis occurs from the outer coat alone functioning, without
there being any kind of pull towards the mouth. For, although the
swallowing of food is ordinarily preceded by a feeling of desire on
the part of the stomach, there is in the case of vomiting no corresponding
desire from the mouth-parts for the experience; the two are opposite
dispositions of the stomach itself; it yearns after and tends towards
what is advantageous and proper to it, it loathes and rids itself
of what is foreign. Thus the actual process of swallowing occurs very
quickly in those who have a good appetite for such foods as are proper
to the stomach; this organ obviously draws them in and down before
they are masticated; whereas in the case of those who are forced to
take a medicinal draught or who take food as medicine, the swallowing
of these articles is accomplished with distress and difficulty.

From what has been said, then, it is clear that the inner coat of
the stomach (that containing longitudinal fibres) exists for the purpose
of exerting a pull the from to stomach, and that it is only in deglutition
that it is active, whereas the external coat, which contains transverse
fibres, has been so constituted in order that it may contract upon
its contents and propel them forward; this coat furthermore, functions
in vomiting no less than in swallowing. The truth of my statement
is also borne out by what happens in the channae and synodonts; the
stomachs of these animals are sometimes found in their mouths, as
also Aristotle writes in his "History of Animals"; he also adds the
cause of this: he says that it is owing to their voracity.

The facts are as follows. In all animals, when the appetite is very
intense, the stomach rises up, so that some people who have a clear
perception of this condition say that their stomach "creeps out" of
them; in others, who are still masticating their food and have not
yet worked it up properly in the mouth, the stomach obviously snatches
away the food from them against their will. In those animals, therefore,
which are naturally voracious, in whom the mouth cavity is of generous
proportions, and the stomach situated close to it (as in the case
of the synodont and channae), it is in no way surprising that, when
they are sufficiently hungry and are pursuing one of the smaller animals,
and are just on the point of catching it, the stomach should, under
the impulse of desire, spring into the mouth. And this cannot possibly
take place in any other way than by the stomach drawing the food to
itself by means of the gullet, as though by a hand. In fact, just
as we ourselves, in our eagerness to grasp more quickly something
lying before us, sometimes stretch out our whole bodies along with
our hands, so also the stomach stretches itself forward along with
the gullet, which is, as it were, its hand. And thus, in these animals
in whom those three factors co-exist- an excessive propensity for
food, a small gullet, and ample mouth proportions- in these, any slight
tendency to movement forwards brings the whole stomach into the mouth.

Now the constitution of the organs might itself suffice to give a
naturalist an indication of their functions. For Nature would never
have purposelessly constructed the oesophagus of two coats with contrary
dispositions; they must also have each been meant to have a different
action. The Erasistratean school, however, are capable of anything
rather than of recognizing the effects of Nature. Come, therefore,
let us demonstrate to them by animal dissection as well that each
of the two coats does exercise the activity which I have stated. Take
an animal, then; lay bare the structures surrounding the gullet, without
severing any of the nerves, arteries, or veins which are there situated;
next divide with vertical incisions, from the lower jaw to the thorax,
the outer coat of the oesophagus (that containing transverse fibres);
then give the animal food and you will see that it still swallows
although the peristaltic function has been abolished. If, again, in
another animal, you cut through both coats with transverse incisions,
you will observe that this animal also swallows although the inner
coat is no longer functioning. From this it is clear that the animal
can also swallow by either of the two coats, although not so well
as by both. For the following also, in addition to other points, may
be distinctly observed in the dissection which I have described- that
during deglutition the gullet becomes slightly filled with air which
is swallowed along with the food, and that, when the outer coat is
contracting, this air is easily forced with the food into the stomach,
but that, when there only exists an inner coat, the air impedes the
conveyance of food, by distending this coat and hindering its action.

But Erasistratus said nothing about this, nor did he point out that
the oblique situation of the gullet clearly confutes the teaching
of those who hold that it is simply by virtue of the impulse from
above that food which is swallowed reaches the stomach. The only correct
thing he said was that many of the longnecked animals bend down to
swallow. Hence, clearly, the observed fact does not show how we swallow
but how we do not swallow. For from this observation it is clear that
swallowing is not due merely to the impulse from above; it is yet,
however, not clear whether it results from the food being attracted
by the stomach, or conducted by the gullet. For our part, however,
having enumerated all the different considerations- those based on
the constitution of the organs, as well as those based on the other
symptoms which, as just mentioned, occur both before and after the
gullet has been exposed- we have thus sufficiently proved that the
inner coast exists for the purpose of attraction and the outer for
the purpose of propulsion. 

Now the original task we set before ourselves was to demonstrate that
the retentive faculty exists in every one of the organs, just as in
the previous book we proved the existence of the attractive, and,
over and above this, the alterative faculty. Thus, in the natural
course of our argument, we have demonstrated these four faculties
existing in the stomach- the attractive faculty in connection with
swallowing, the retentive with digestion, the expulsive with vomiting
and with the descent of digested food into the small intestine- and
digestion itself we have shown to be a process of alteration.

9. Concerning the spleen, also, we shall therefore have no further
doubts as to whether it attracts what is proper to it, rejects what
is foreign, and has a natural power of altering and retaining all
that it attracts; nor shall we be in any doubt as to the liver, veins,
arteries, heart, or any other organ. For these four faculties have
been shown to be necessary for every part which is to be nourished;
this is why we have called these faculties the handmaids of nutrition.
For just as human faeces are most pleasing to dogs, so the residual
matters from the liver are, some of them, proper to the spleen, others
to the gall-bladder, and others to the kidneys. 

10. I should not have cared to say anything further as to the origin
of these [surplus substances] after Hippocrates, Plato, Aristotle,
Diocles, Praxagoras, and Philotimus, nor indeed should I even have
said anything about the faculties, if any of our predecessors had
worked out this subject thoroughly. 

While, however, the statements which the Ancients made on these points
were correct, they yet omitted to defend their arguments with logical
proofs; of course they never suspected that there could be sophists
so shameless as to try to contradict obvious facts. More recent physicians,
again, have been partly conquered by the sophistries of these fellows
and have given credence to them; whilst others who attempted to argue
with them appear to me to lack to a great extent the power of the
Ancients. For this reason I have attempted to put together my arguments
in the way in which it seems to me the Ancients, had any of them been
still alive, would have done, in opposition to those who would overturn
the finest doctrines of our art. 

I am not, however, unaware that I shall achieve either nothing at
all or else very little. For I find that a great many things which
have been conclusively demonstrated by the Ancients are unintelligible
to the bulk of the Moderns owing to their ignorance- nay, that, by
reason of their laziness, they will not even make an attempt to comprehend
them; and even if any of them have understood them, they have not
given them impartial examination. 

The fact is that he whose purpose is to know anything better than
the multitude do must far surpass all others both as regards his nature
and his early training. And when he reaches early adolescence he must
become possessed with an ardent love for truth, like one inspired;
neither day nor night may he cease to urge and strain himself in order
to learn thoroughly all that has been said by the most illustrious
of the Ancients. And when he has learnt this, then for a prolonged
period he must test and prove it, observing what part of it is in
agreement, and what in disagreement with obvious fact; thus he will
choose this and turn away from that. To such an one my hope has been
that my treatise would prove of the very greatest assistance.... Still,
such people may be expected to be quite few in number, while, as for
the others, this book will be as superfluous to them as a tale told
to an ass. 

11. For the sake, then, of those who are aiming at truth, we must
complete this treatise by adding what is still wanting in it. Now,
in people who are very hungry, the stomach obviously attracts or draws
down the food before it has been thoroughly softened in the mouth,
whilst in those who have no appetite or who are being forced to eat,
the stomach is displeased and rejects the food. And in a similar way
of the other organs possesses both faculties- that of attracting what
is proper to it, and that of rejecting what is foreign. Thus, even
if there be any organ which consists of only one coat (such as the
two bladders, the uterus, and the veins), it yet possesses both kinds
of fibres, the longitudinal and the transverse.

But further, there are fibres of a third kind- the oblique- which
are much fewer in number than the two kinds already spoken of. In
the organs consisting of two coats this kind of fibre is found in
the one coat only, mixed with the longitudinal fibres; but in the
organs composed of one coat it is found along with the other two kinds.
Now, these are of the greatest help to the action of the faculty which
we have named retentive. For during this period the part needs to
be tightly contracted and stretched over its contents at every point-
the stomach during the whole period of digestion, and the uterus during
that of gestation. 

Thus too, the coat of a vein, being single, consists of various kinds
of fibres; whilst the outer coat of an artery consists of circular
fibres, and its inner coat mostly of longitudinal fibres, but with
a few oblique ones also amongst them. Veins thus resemble the uterus
or the bladder as regards the arrangement of their fibres, even though
they are deficient in thickness; similarly arteries resemble the stomach.
Alone of all organs the intestines consist of two coats of which both
have their fibres transverse. Now the proof that it was for the best
that all the organs should be naturally such as they are (that, for
instance, the intestines should be composed of two coats) belongs
to the subject of the use of parts; thus we must not now desire to
hear about matters of this kind nor why the anatomists are at variance
regarding the number of coats in each organ. For these questions have
been sufficiently discussed in the treatise "On Disagreement in Anatomy."
And the problem as to why each organ has such and such a character
will be discussed in the treatise "On the Use of Parts."

12. It is not, however, our business to discuss either of these questions
here, but to consider duly the natural faculties, which, to the number
of four, exist in each organ. Returning then, to this point, let us
recall what has already been said, and set a crown to the whole subject
by adding what is still wanting. For when every part of the animal
has been shewn to draw into itself the juice which is proper to it
(this being practically the first of the natural faculties), the next
point to realise is that the part does not get rid either of this
attracted nutriment as a whole, or even of any superfluous portion
of it, until either the organ itself, or the major part of its contents
also have their condition reversed. Thus, when the stomach is sufficiently
filled with the food and has absorbed and stored away the most useful
part of it in its own coats, it then rejects the rest like an alien
burden. The same happens to the bladders, when the matter attracted
into them begins to give trouble either because it distends them through
its quantity or irritates them by its quality. 

And this also happens in the case of the uterus; for it is either
because it can no longer bear to be stretched that it strives to relieve
itself of its annoyance, or else because it is irritated by the quality
of the fluids poured out into it. Now both of these conditions sometimes
occur with actual violence, and then miscarriage takes place. But
for the most part they happen in a normal way, this being then called
not miscarriage but delivery or parturition. Now abortifacient drugs
or certain other conditions which destroy the embryo or rupture certain
of its membranes are followed by abortion, and similarly also when
the uterus is in pain from being in a bad state of tension; and, as
has been well said by Hippocrates, excessive movement on the part
of the embryo itself brings on labour. Now pain is common to all these
conditions, and of this there are three possible causes- either excessive
bulk, or weight, or irritation; bulk when the uterus can no longer
support the stretching, weight when the contents surpass its strength,
and irritation when the fluids which had previously been pent up in
the membranes, flow out, on the rupture of these, into the uterus
itself, or else when the whole foetus perishes, putrefies, and is
resolved into pernicious ichors, and so irritates and bites the coat
of the uterus. 

In all organs, then, both their natural effects and their disorders
and maladies plainly take place on analogous lines, some so clearly
and manifestly as to need no demonstration, and others less plainly,
although not entirely unrecognizable to those who are willing to pay
attention. 

Thus, to take the case of the stomach: the irritation is evident here
because this organ possesses most sensibility, and among its other
affections those producing nausea and the so-called heartburn clearly
demonstrate the eliminative faculty which expels foreign matter. So
also in the case of the uterus and the urinary bladder; this latter
also may be plainly observed to receive and accumulate fluid until
it is so stretched by the amount of this as to be incapable of enduring
the pain; or it may be the quality of the urine which irritates it;
for every superfluous substance which lingers in the body must obviously
putrefy, some in a shorter, and some in a longer time, and thus it
becomes pungent, acrid, and burdensome to the organ which contains
it. This does not apply, however, in the case of the bladder alongside
the liver, whence it is clear that it possesses fewer nerves than
do the other organs. Here too, however, at least the physiologist
must discover an analogy. For since it was shown that the gall-bladder
attracts its own special juice, so as to be often found full, and
that it discharges it soon after, this desire to discharge must be
either due to the fact that it is burdened by the quantity or that
the bile has changed in quality to pungent and acrid. For while food
does not change its original quality so fast that it is already ordure
as soon as it falls into the small intestine, on the other hand the
bile even more readily than the urine becomes altered in quality as
soon as ever it leaves the veins, and rapidly undergoes change and
putrefaction. Now, if there be clear evidence in relation to the uterus,
stomach, and intestines, as well as to the urinary bladder, that there
is either some distention, irritation, or burden inciting each of
these organs to elimination, there is no difficulty in imagining this
in the case of the gall-bladder also, as well as in the other organs,-
to which obviously the arteries and veins also belong. 

13. Nor is there any further difficulty in ascertaining that it is
through the same channel that both attraction and discharge take place
at different times. For obviously the inlet to the stomach does not
merely conduct food and drink into this organ, but in the condition
of nausea it performs the neck of the bladder which is beside the
liver, albeit single, both fills and empties the bladder. Similarly
the canal of the uterus affords an entrance to the semen and an exit
to the foetus. 

But in this latter case, again, whilst the eliminative faculty is
evident, the attractive faculty is not so obvious to most people.
It is, however, the cervix which Hippocrates blames for inertia of
the uterus when he says:- "Its orifice has no power of attracting
semen." 

Erasistratus, however, and Asclepiades reached such heights of wisdom
that they deprived not merely the stomach and the womb of this faculty
but also the bladder by the liver, and the kidneys as well. I have,
however, pointed out in the first book that it is impossible to assign
any other cause for the secretion of urine or bile. 

Now, when we find that the uterus, the stomach and the bladder by
the liver carry out attraction and expulsion through one and the same
duct, we need no longer feel surprised that Nature should also frequently
discharge waste-substances into the stomach through the veins. Still
less need we be astonished if a certain amount of the food should,
during long fasts, be drawn back from the liver into the stomach through
the same veins by which it was yielded up to the liver during absorption
of nutriment. To disbelieve such things would of course be like refusing
to believe that purgative drugs draw their appropriate humours from
all over the body by the same stomata through which absorption previously
takes place, and to look for separate stomata for absorption and purgation
respectively. As a matter of fact one and the same stoma subserves
two distinct faculties, and these exercise their pull at different
times in opposite directions- first it subserves the pull of the liver
and, during catharsis, that of the drug. What is there surprising,
then, in the fact that the veins situated between the liver and the
region of the stomach fulfil a double service or purpose? Thus, when
there is abundance of nutriment contained in the food-canal, it is
carried up to the liver by the veins mentioned; and when the canal
is empty and in need of nutriment, this is again attracted from the
liver by the same veins. 

For everything appears to attract from and to go shares with everything
else, and, as the most divine Hippocrates has said, there would seem
to be a consensus in the movements of fluids and vapours. Thus the
stronger draws and the weaker is evacuated. 

Now, one part is weaker or stronger than another either absolutely,
by nature, and in all cases, or else it becomes so in such and such
a particular instance. Thus, by nature and in all men alike, the heart
is stronger than the liver at attracting what is serviceable to it
and rejecting what is not so; similarly the liver is stronger than
the intestines and stomach, and the arteries than the veins. In each
of us personally, however, liver has stronger drawing power at one
time, and the stomach at another. For when there is much nutriment
contained in the alimentary canal and the appetite and craving of
the liver is violent, then the viscus exerts far the strongest traction.
Again, when the liver is full and distended and the stomach empty
and in need, then the force of the traction shifts to the latter.

Suppose we had some food in our hands and were snatching it from one
another; if we were equally in want, the stronger would be likely
to prevail, but if he had satisfied his appetite, and was holding
what was over carelessly, or was anxious to share it with somebody,
and if the weaker was excessively desirous of it, there would be nothing
to prevent the latter from getting it all. In a similar manner the
stomach easily attracts nutriment from the liver when it [the stomach]
has a sufficiently strong craving for it, and the appetite of the
viscus is satisfied. And sometimes the surplusage of nutriment in
the liver is a reason why the animal is not hungry; for when the stomach
has better and more available food it requires nothing from extraneous
sources, but if ever it is in need and is at a loss how to supply
the need, it becomes filled with waste-matters; these are certain
biliary, phlegmatic [mucous] and serous fluids, and are the only substances
that the liver yields in response to the traction of the stomach,
on the occasions when the latter too is in want of nutriment.

Now, just as the parts draw food from each other, so also they sometimes
deposit their excess substances in each other, and just as the stronger
prevailed when the two were exercising traction, so it is also when
they are depositing; this is the cause of the so-called fluxions,
for every part has a definite inborn tension, by virtue of which it
expels its superfluities, and, therefore, when one of these parts,-
owing, of course, to some special condition- becomes weaker, there
will necessarily be a confluence into it of the superfluities from
all the other parts. The strongest part deposits its surplus matter
in all the parts near it; these again in other parts which are weaker;
these next into yet others; and this goes on for a long time, until
the superfluity, being driven from one part into another, comes to
rest in one of the weakest of all; it cannot flow from this into another
part, because none of the stronger ones will receive it, while the
affected part is unable to drive it away. 

When, however, we come to deal again with the origin and cure of disease,
it will be possible to find there also abundant proofs of all that
we have correctly indicated in this book. For the present, however,
let us resume again the task that lay before us, i.e. to show that
there is nothing surprising in nutriment coming from the liver to
the intestines and stomach by way of the very veins through which
it had previously been yielded up from these organs into the liver.
And in many people who have suddenly and completely given up active
exercise, or who have had a limb cut off, there occurs at certain
periods an evacuation of blood by way of the intestines- as Hippocrates
has also pointed out somewhere. This causes no further trouble but
sharply purges the whole body and evacuates the plethoras; the passage
of the superfluities is effected, of course, through the same veins
by which absorption took place. 

Frequently also in disease Nature purges the animal through these
same veins- although in this case the discharge is not sanguineous,
but corresponds to the humour which is at fault. Thus in cholera the
entire body is evacuated by way of the veins leading to the intestines
and stomach. 

To imagine that matter of different kinds is carried in one direction
only would characterise a man who was entirely ignorant of all the
natural faculties, and particularly of the eliminative faculty, which
is the opposite of the attractive. For opposite movements of matter,
active and passive, must necessarily follow opposite faculties; that
is to say, every part, after it has attracted its special nutrient
juice and has retained and taken the benefit of it hastens to get
rid of all the surplusage as quickly and effectively as possible,
and this it does in accordance with the mechanical tendency of this
surplus matter. 

Hence the stomach clears away by vomiting those superfluities which
come to the surface of its contents, whilst the sediment it clears
away by diarrhoea. And when the animal becomes sick, this means that
the stomach is striving to be evacuated by vomiting. And the expulsive
faculty has in it so violent and forcible an element that in cases
of ileus [volvulus], when the lower exit is completely closed, vomiting
of faeces occurs; yet such surplus matter could not be emitted from
the mouth without having first traversed the whole of the small intestine,
the jejunum, the pylorus, the stomach, and the oesophagus. What is
there to wonder at, then, if something should also be transferred
from the extreme skin-surface and so reach the intestines and stomach?
This also was pointed out to us by Hippocrates, who maintained that
not merely pneuma or excess-matter, but actual nutriment is brought
down from the outer surface to the original place from which it was
taken up. For the slightest mechanical movements determine this expulsive
faculty, which apparently acts through the transverse fibres, and
which is very rapidly transmitted from the source of motion to the
opposite extremities. It is, therefore, neither unlikely nor impossible
that, when the part adjoining the skin becomes suddenly oppressed
by an unwonted cold, it should at once be weakened and should find
that the liquid previously deposited beside it without discomfort
had now become more of a burden than a source of nutrition, and should
therefore strive to put it away. Finally, seeing that the passage
outwards was shut off by the condensation [of tissue], it would turn
to the remaining exit and would thus forcibly expel all the waste-matter
at once into the adjacent part; this would do the same to the part
following it; and the process would not cease until the transference
finally terminated at the inner of the veins. 

Now, movements like these come to an end fairly soon, but those resulting
from internal irritants (e.g., in the administration of purgative
drugs or in cholera) become much stronger and more lasting; they persist
as long as the condition of things about the mouths of the veins continues,
that is, so long as these continue to attract what is adjacent. For
this condition causes evacuation of the contiguous part, and that
again of the part next to it, and this never stops until the extreme
surface is reached; thus, as each part keeps passing on matter to
its neighbour, the original affection very quickly arrives at the
extreme termination. Now this is also the case in ileus; the inflamed
intestine is unable to support either the weight or the acridity of
the waste substances and so does its best to excrete them, in fact
to drive them as far away as possible. And, being prevented from effecting
an expulsion downwards when the severest part of the inflammation
is there, it expels the matter into the adjoining part of the intestines
situated above. Thus the tendency of the eliminative faculty is step
by step upwards, until the superfluities reach the mouth.

Now this will be also spoken of at greater length in my treatise on
disease. For the present, however, I think I have shown clearly that
there is a universal conveyance or transference from one thing into
another, and that, as Hippocrates used to say, there exists in everything
a consensus in the movement of air and fluids. And I do not think
that anyone, however slow his intellect, will now be at a loss to
understand any of these points,- how, for instance, the stomach or
intestines get nourished, or in what manner anything makes its way
inwards from the outer surface of the body. Seeing that all parts
have the faculty of attracting what is suitable or well-disposed and
of eliminating what is troublesome or irritating, it is not surprising
that opposite movements should occur in them consecutively- as may
be clearly seen in the case of the heart, in the various arteries,
in the thorax, and lungs. In all these the active movements of the
organs and therewith the passive movements of [their contained] matters
may be seen taking place almost every second in opposite directions.
Now, you are not astonished when the trachea-artery alternately draws
air into the lungs and gives it out, and when the nostrils and the
whole mouth act similarly; nor do you think it strange or paradoxical
that the air is dismissed through the very channel by which it was
admitted just before. Do you, then, feel a difficulty in the case
of the veins which pass down from the liver into the stomach and intestines,
and do you think it strange that nutriment should at once be yielded
up to the liver and drawn back from it into the stomach by the same
veins? You must define what you mean by this expression "at once."
If you mean "at the same time" this is not what we ourselves say;
for just as we take in a breath at one moment and give it out again
at another, so at one time the liver draws nutriment from the stomach,
and at another the stomach from the liver. But if your expression
"at once" means that in one and the same animal a single organ subserves
the transport of matter in opposite directions, and if it is this
which disturbs you, consider inspiration and expiration. For of course
these also take place through the same organs, albeit they differ
in their manner of movement, and in the way in which the matter is
conveyed through them. 

Now the lungs, the thorax, the arteries rough and smooth, the heart,
the mouth, and the nostrils reverse their movements at very short
intervals and change the direction of the matters they contain. On
the other hand, the veins which pass down the from the liver to the
intestines and stomach reverse the direction not at such short intervals,
but sometimes once in many days. 

The whole matter, in fact, is as follows:- Each of the organs draws
into itself the nutriment alongside it, and devours all the useful
fluid in it, until it is thoroughly satisfied; this nutriment, as
I have already shown, it stores up in itself, afterwards making it
adhere and then assimilating it- that is, it becomes nourished by
it. For it has been demonstrated with sufficient clearness already
that there is something which necessarily precedes actual nutrition,
namely adhesion, and that before this again comes presentation. Thus
as in the case of the animals themselves the end of eating is that
the stomach should be filled, similarly in the case of each of the
parts, the end of presentation is the filling of this part with its
appropriate liquid. Since, therefore, every part has, like the stomach,
a craving to be nourished, it too envelops its nutriment and clasps
it all round as the stomach does. And this [action of the stomach],
as has been already said, is necessarily followed by the digestion
of the food, although it is not to make it suitable for the other
parts that the stomach contracts upon it; if it did so, it would no
longer be a physiological organ, but an animal possessing reason and
intelligence, with the power of choosing the better [of two alternatives].

But while the stomach contracts for the reason that the whole body
possesses a power of attracting and of utilising appropriate qualities,
as has already been explained, it also happens that, in this process,
the food undergoes alteration; further, when filled and saturated
with the fluid pabulum from the food, it thereafter looks on the food
as a burden; thus it at once gets of the excess- that is to say, drives
it gets downwards- itself turning to another task, namely that of
causing adhesion. And during this time, while the nutriment is passing
along the whole length of the intestine, it is caught up by the vessels
which pass into the intestine; as we shall shortly demonstrate, most
of it is seized by the veins, but a little also by the arteries; at
this stage also it becomes presented to the coats of the intestines.

Now imagine the whole economy of nutrition divided into three periods.
Suppose that in the first period the nutriment remains in the stomach
and is digested and presented to the stomach until satiety is reached,
also that some of it is taken up from the stomach to the liver.

During the second period it passes along the intestines and becomes
presented both to them and to the liver- again until the stage of
satiety- while a small part of it is carried all over the body. During
this period, also imagine that what was presented to the stomach in
the first period becomes now adherent to it. 

During the third period the stomach has reached the stage of receiving
nourishment; it now entirely assimilates everything that had become
adherent to it: at the same time in the intestines and liver there
takes place adhesion of what had been before presented, while dispersal
[anadosis] is taking place to all parts of the body, as also presentation.
Now, if the animal takes food immediately after these [three stages]
then, during the time that the stomach is again digesting and getting
the benefit of this by presenting all the useful part of it to its
own coats, the intestines will be engaged in final assimilation of
the juices which have adhered to them, and so also will the liver:
while in the various parts of the body there will be taking place
adhesion of the portions of nutriment presented. And if the stomach
is forced to remain without food during this time, it will draw its
nutriment the from the veins in the mesentery and liver; for it will
not do so from the actual body of the liver (by body of the liver
I mean first and foremost its flesh proper, and after this all the
vessels contained in it), for it is irrational to suppose that one
part would draw away from another part the juice already contained
in it, especially when adhesion and final assimilation of that juice
were already taking place; the juice, however, that is in the cavity
of the veins will be abstracted by the part which is stronger and
more in need. 

It is in this way, therefore, that the stomach, when it is in need
of nourishment and the animal has nothing to eat, seizes it from the
veins in the liver. Also in the case of the spleen we have shown in
a former passage how it draws all material from the liver that tends
to be thick, and by working it up converts it into more useful matter.
There is nothing surprising, therefore, if, in the present instance
also, some of this should be drawn from the spleen into such organs
as communicate with it by veins, e.g. the omentum, mesentery, small
intestine, colon, and the stomach itself. Nor is it surprising that
the spleen should disgorge its surplus matters into the stomach at
one time, while at another time it should draw some of its appropriate
nutriment from the stomach. 

For, as has already been said, speaking generally, everything has
the power at different times of attracting from and of adding to everything
else. What happens is just as if you might imagine a number of animals
helping themselves at will to a plentiful common stock of food; some
will naturally be eating when others have stopped, some will be on
the point of stopping when others are beginning, some eating together,
and others in succession. Yes, by Zeus! and one will often be plundering
another, if he be in need while the other has an abundant supply ready
to hand. Thus it is in no way surprising that matter should make its
way back from the outer surface of the body to the interior, or should
be carried from the liver and spleen into the stomach by the same
vessels by which it was carried in the reverse direction.

In the case of the arteries this is clear enough, as also in the case
of heart, thorax, and lungs; for, since all of these dilate and contract
alternately, it must needs be that matter is subsequently discharged
back into the parts from which it was previously drawn. Now Nature
foresaw this necessity, and provided the cardiac openings of the vessels
with membranous attachments, to prevent their contents from being
carried backwards. How and in what manner this takes place will be
stated in my work "On the Use of Parts," where among other things
I show that it is impossible for the openings of the vessels to be
closed so accurately that nothing at all can run back. Thus it is
inevitable that the reflux into the venous artery (as will also be
made clear in the work mentioned) should be much greater than through
the other openings. But what it is important for our present purpose
to recognise is that every thing possessing a large and appreciable
cavity must, when it dilates, abstract matter from all its neighbours,
and, when it contracts, must squeeze matter back into them. This should
all be clear from what has already been said in this treatise and
from what Erasistratus and I myself have demonstrated elsewhere respecting
the tendency of a vacuum to become refilled. 

14. And further, it has been shown in other treatises that all the
arteries possess a power which derives from the heart, and by virtue
of which they dilate and contract. 

Put together, therefore, the two facts- that the arteries have this
motion, and that everything, when it dilates, draws neighbouring matter
into itself- and you will find nothing strange in the fact that those
arteries which reach the skin draw in the outer air when they dilate,
while those which anastomose at any point with the veins attract the
thinnest and most vaporous part of the blood which these contain,
and as for those arteries which are near the heart, it is on the heart
itself that they exert their traction. For, by virtue of the tendency
by which a vacuum becomes refilled, the lightest and thinnest part
obeys the tendency before that which is heavier and thicker. Now the
lightest and thinnest of anything in the body is firstly pneuma, secondly
vapour, and in the third place that part of the blood which has been
accurately elaborated and refined. 

These, then, are what the arteries draw into themselves on every side;
those arteries which reach the skin draw in the outer air (this being
near them and one of the lightest of things); as to the other arteries,
those which pass up from the heart into the neck, and that which lies
along the spine, as also such arteries as are near these- draw mostly
from the heart itself; and those which are farther from the heart
and skin necessarily draw the lightest part of the blood out of the
veins. So also the traction exercised by the diastole of the arteries
which go to the stomach and intestines takes place at the expense
of the heart itself and the numerous veins in its neighbourhood; for
these arteries cannot get anything worth speaking of from the thick
heavy nutriment contained in the intestines and stomach, since they
first become filled with lighter elements. For if you let down a tube
into a vessel full of water and sand, and suck the air out of the
tube with your mouth, the sand cannot come up to you before the water,
for in accordance with the principle of the refilling of a vacuum
the lighter matter is always the first to succeed to the evacuation.

15. is not to be wondered at, therefore, that only a very little [nutrient
matter] such, namely, as has been accurately elaborated- gets from
the stomach into the arteries, since these first become filled with
lighter matter. We must understand that there are two kinds of attraction,
that by which a vacuum becomes refilled and that caused by appropriateness
of quality; air is drawn into bellows in one way, and iron by the
lodestone in another. And we must also understand that the traction
which results from evacuation acts primarily on what is light, whilst
that from appropriateness of quality acts frequently, it may be, on
what is heavier (if this should be naturally more nearly related).
Therefore, in the case of the heart and the arteries, it is in so
far as they are hollow organs, capable of diastole, that they always
attract the lighter matter first, while, in so far as they require
nourishment, it is actually into their coats (which are the real bodies
of these organs) that the appropriate matter is drawn. Of the blood,
then, which is taken into their cavities when they dilate, that part
which is most proper to them and most able to afford nourishment is
attracted by their actual coats. 

Now, apart from what has been said, the following is sufficient proof
that something is taken over from the veins into the arteries. If
you will kill an animal by cutting through a number of its large arteries,
you will find the veins becoming empty along with the arteries: now,
this could never occur if there were not anastomoses between them.
Similarly, also, in the heart itself, the thinnest portion of the
blood is drawn from the right ventricle into the left, owing to there
being perforations in the septum between them: these can be seen for
a great part [of their length]; they are like a kind of fossae [pits]
with wide mouths, and they get constantly narrower; it is not possible,
however, actually to observe their extreme terminations, owing both
to the smallness of these and to the fact that when the animal is
dead all the parts are chilled and shrunken. Here, too, however, our
argument, starting from the principle that nothing is done by Nature
in vain, discovers these anastomoses between the ventricles of the
heart; for it could not be at random and by chance that there occurred
fossae ending thus in narrow terminations. 

And secondly [the presence of these anastomoses has been assumed]
from the fact that, of the two orifices in the right ventricle, the
one conducting blood in and the other out, the former is much the
larger. For, the fact that the insertion of the vena cava into the
heart is larger than the vein which is inserted into the lungs suggests
that not all the blood which the vena cava gives to the heart is driven
away again from the heart to the lungs. Nor can it be said that any
of the blood is expended in the nourishment of the actual body of
the heart, since there is another vein which breaks up in it and which
does not take its origin nor get its share of blood from the heart
itself. And even if a certain amount is so expended, still the vein
leading to the lungs is not to such a slight extent smaller than that
inserted into the heart as to make it likely that the blood is used
as nutriment for the heart: the disparity is much too great for such
an explanation. It is, therefore, clear that something is taken over
into the left ventricle. 

Moreover, of the two vessels connected with it, that which brings
pneuma into it from the lungs is much smaller than the great outgrowing
artery from which the arteries all over the body originate; this would
suggest that it not merely gets pneuma from the lungs, but that it
also gets blood from the right ventricle through the anastomoses mentioned.

Now it belongs to the treatise "On the Use of Parts" to show that
it was best that some parts of the body should be nourished by pure,
thin, and vaporous blood, and others by thick, turbid blood, and that
in this matter also Nature has overlooked nothing. Thus it is not
desirable that these matters should be further discussed. Having mentioned,
however, that there are two kinds of attraction, certain bodies exerting
attraction along wide channels during diastole (by virtue of the principle
by which a vacuum becomes refilled) and others exerting it by virtue
of their appropriateness of quality, we must next remark that the
former bodies can attract even from a distance, while the latter can
only do so from among things which are quite close to them; the very
longest tube let down into water can easily draw up the liquid into
the mouth, but if you withdraw iron to a distance from the lodestone
or corn from the jar (an instance of this kind has in fact been already
given) no further attraction can take place. 

This you can observe most clearly in connection with garden conduits.
For a certain amount of moisture is distributed from these into every
part lying close at hand but it cannot reach those lying farther off:
therefore one has to arrange the flow of water into all parts of the
garden by cutting a number of small channels leading from the large
one. The intervening spaces between these small channels are made
of such a size as will, presumably, best allow them [the spaces] to
satisfy their needs by drawing from the liquid which flows to them
from every side. So also is it in the bodies of animals. Numerous
conduits distributed through the various limbs bring them pure blood,
much like the garden water-supply, and, further, the intervals between
these conduits have been wonderfully arranged by Nature from the outset
so that the intervening parts should be plentifully provided for when
absorbing blood, and that they should never be deluged by a quantity
of superfluous fluid running in at unsuitable times. 

For the way in which they obtain nourishment is somewhat as follows.
In the body which is continuous throughout, such as Erasistratus supposes
his simple vessel to be, it is the superficial parts which are the
first to make use of the nutriment with which they are brought into
contact; then the parts coming next draw their share from these by
virtue of their contiguity; and again others from these; and this
does not stop until the quality of the nutrient substance has been
distributed among all parts of the corpuscle in question. And for
such parts as need the humour which is destined to nourish them to
be altered still further, Nature has provided a kind of storehouse,
either in the form of a central cavity or else as separate caverns,
or something analogous to caverns. Thus the flesh of the viscera and
of the muscles is nourished from the blood directly, this having undergone
merely a slight alteration; the bones, however, in order to be nourished,
very great change, and what blood is to flesh marrow is to bone; in
the case of the small bones, which do not possess central cavities,
this marrow is distributed in their caverns, whereas in the larger
bones which do contain central cavities the marrow is all concentrated
in these. 

For, as was pointed out in the first book, things having a similar
substance can easily change into one another, whereas it is impossible
for those which are very different to be assimilated to one another
without intermediate stages. Such a one in respect to cartilage is
the myxoid substance which surrounds it, and in respect to ligaments,
membranes, and nerves the viscous liquid dispersed inside them; for
each of these consists of numerous fibres, which are homogeneous-
in fact, actual sensible elements; and in the intervals between these
fibres is dispersed the humour most suited for nutrition; this they
drawn from the blood in the veins, choosing the most appropriate possible,
and now they are assimilating it step by step and changing it into
their own substance. 

All these considerations, then, agree with one another, and bear sufficient
witness to the truth of what has been already demonstrated; there
is thus no need to prolong the discussion further. For, from what
has been said, anyone can readily discover in what way all the particular
[vital activities] come about. For instance, we could in this way
ascertain why it is that in the case of many people who are partaking
freely of wine, the fluid which they have drunk is rapidly absorbed
through the body and almost the whole of it is passed by the kidneys
within a very short time. For here, too, the rapidity with which the
fluid is absorbed depends on appropriateness of quality, on the thinness
of the fluid, on the width of the vessels and their mouths, and on
the efficiency of the attractive faculty. The parts situated near
the alimentary canal, by virtue of their appropriateness of quality,
draw in the imbibed food for their own purposes, then the parts next
to them in their turn snatch it away, then those next again take it
from these, until it reaches the vena cava, whence finally the kidneys
attract that part of it which is proper to them. Thus it is in no
way surprising that wine is taken up more rapidly than water, owing
to its appropriateness of quality, and, further, that the white clear
kind of wine is absorbed more rapidly owing to its thinness, while
black turbid wine is checked on the way and retarded because of its
thickness. 

These facts, also, will afford abundant proof of what has already
been said about the arteries; everywhere, in fact, such blood as is
both specifically appropriate and at the same time thin in consistency
answers more readily to their traction than does blood which is not
so; this is why the arteries which, in their diastole, absorb vapour,
pneuma, and thin blood attract either none at all or very little of
the juices contained in the stomach and intestines.