The marks of a preternatural dryness of the stomach are, that those
affected with it are liable to thirst, but little drink satisfies them;
and they feel heavy with much drink, as the superfluity occasions
gurgling in the stomach, or floats upon it; of those of a more humid,
that they are not addicted to thirst, and bear readily much liquids,
and rejoice in humid food. A stomach preternaturally hot has a better
digestion than appetite, particularly with regard to those things which
are hard and difficult to digest; it delights in much food and drink;
neither is it hurt by the moderate use of cold things. A preternaturally
cold stomach has a good appetite but not a good digestion, in particular
with regard to such things as are of difficult digestion, and are of a
cold nature, which therefore are apt to turn acid in it. And it delights
indeed in cold things, but is readily hurt by the immoderate use of them.
The intemperaments proceeding from disease differ from the congenital
in this, that they long for opposite things, and not always alike. If
the stomach then digests properly, it is of a moderate temperament; and
if it does not it is of a bad; but if its eructations are fetid, its
heat is inordinate and inflammatory; but if acid, the contrary. And in
those who digest properly things of difficult digestion, the heat of the
stomach is inordinate, and weak in those who cannot digest those things,
but digest fishes. It must also be observed, whether or not the symptom
is occasioned by any humour flowing from another part; for in pituitous
constitutions acid eructations are apt to occur; but in the bilious,
fetid airs and other disagreeable qualities are apt to prevail. The
common symptom of them all is nausea. If the depraved humours swim within
the cavity of the stomach, they float on the surface, and are discharged
by vomiting; but if they are contained in the substance of it within its
coats, they annoy it with vain attempts to vomit.
* * * * *
COMMENTARY. We shall now state briefly the opinions of the ancients with
regard to the functional office of the stomach.
Actuarius says, “I am of opinion, that there are four species of
concoction which are performed in different parts of the body: the first
in the stomach; the second in the vena ramalis (vena portæ?), meseraic
veins, and concave part of the liver; the third in the convex part of
the liver and veins proceeding from it; and the fourth, consisting of
fabrication or assimilation, which takes place in the extreme parts of
the body.” (De Urinis.) The various modes of change or concoction which
the food undergoes in the body, are minutely described by Macrobius.
(Saturnal. vii.) In another place, Actuarius says, “Digestion is
performed by moderate heat and moisture.” (De Spiritu Animali, p. ii,
s. 1.) Alsaharavius in like manner states, that the digestive faculty
depends partly on the heat, and partly on the humidity of the stomach.
(Pract. tr. xvi, c. 1.) It is impossible not to see that the gastric
juice is alluded to in these passages. It is particularly stated of
Asclepiades, that he held digestion to be the solution of the food. See
C. Aurelianus. (Morb. Acut. i, 14.) And that the ancients were aware
that the stomach secretes a fluid possessed of solvent properties, is
put beyond a doubt, by the following extract from the works of Haly
Abbas. Speaking of the changes which the food undergoes in the mouth and
stomach, he says: “Immutantur cibi in ore, retinenturque, et flegmati
admiscetur quod digestum est, calorque ei datur. Quod autem flegma hoc
hujusmodi sit, signum nobis est quod impetigines et sarpedones curat,
quædam maturat ulcera, scorpiones necat. Hac ergo de causa et in ore
cibus immutatur. Sic et stomachus ipsum immutat: ejus etenim circum
amplectitur substantia, quasque habet imprimit qualitates, immutaturque
ipsius naturali calore cibus: _Sed et quoniam cibus ipse in eo flegmati
admiscetur humido._” (Theor. iv, 3.) The whole bearing of this passage,
but more especially the last clause, puts it beyond a doubt that the
process of digestion was supposed to be performed, in a certain measure,
by the solvent powers of a fluid secreted in the stomach. And the
ingenious Alexander Aphrodisiensis, in like manner, treating of the
digestion of mustard, pepper, and other acrid substances, says decidedly,
that their acrimony is dissolved in the copious fluid of the stomach.
(Probl. i, 30.) See also Macrobius (Saturnal. vii, 8.) He calls the fluid
ventralis humor, which may be literally translated, “gastric juice.” Part
of the process was, no doubt, supposed to be performed indirectly by
heat; and deservedly, for even Spallanzani was compelled to admit, that
the comparative temperature of animals exerts a considerable influence
on their digestive powers. Hence, as was stated by Averrhoes, and as
is confirmed by Cuvier, Birds, which are the warmest class of animals,
likewise digest the fastest. At all events, the ancients were well aware,
that digestion is not a mechanical, but a vital process, being performed
by the principle of life. “Digestion,” says Averrhoes, “is performed by
concoction, and the concoction is influenced by heat, not that the first
mover in the operation is heat, but the nutritive soul; because the
operations of heat are indeterminate, and not directed to any manifest
end.” (Collig. v, 3.) In the ‘Averroeana’ or ‘Letters from Averrhoes
to Metrodorus,’ (which, whether genuine or not, contain a curious and
interesting exposition of the _Great Commentator’s_ opinions on various
subjects, and at all events must be of considerable antiquity,) the
doctrine of a gastric menstruum is discussed with singular ability.
Metrodorus states, that “he found, by the writings of the physicians and
philosophers of these times, that they make the _menstruum_, as they
call it, whereby both appetite is provoked, and food in the stomach is
digested, to be a certain juice or humour in the stomach,” &c. Averrhoes
denies that this menstruum acts by its acidity alone.