398 Dr. Knox on the Structure of 
tended merely to prolong its residence within the canal; and a 
fourth finally to convert it into that semi-fluid condition into which 
it is presumed finally to be changed, previous to its passage into 
the intestinal tube ; but still it is one organ, nor have I ever heard 
it affirmed by any one, that the complex quadruple stomach did 
more than the simple stomach in affecting the materiel of our 
nourishment, or bringing it nearer to perfection. I presume, there- 
fore, that the organ is single, in every important sense of the word, 
and that the phraseology of two, three, or four stomachs, is altoge- 
ther incorrect. We have seen that no anatomist of ancient or mo- 
dern times, could ever predict what kind of stomach would neces- 
sarily be found in any animal previous to its having actually been 
examined. The stomach of the elephant presents one large cavity ; 
the elephant has no cutting incisor teeth in either jaw. The sto- 
mach of the horse is single, as the phrase goes, if we require that a 
stomach, to be considered double, must be divided by a permanent- 
ly contracted interval into two cavities, communicating with each 
other by an aperture smaller in diameter than either ; but if to 
constitute a double stomach it be merely necessary that its interior 
should present differently organized surfaces, then the stomach of 
the herse is double. The hippopotamus has, if I remember right, 
as it were, three cavities, or stomachs as they are called, judging by 
the number of culs de sac or compartments ; but I could not observe, 
in the interior of these cavities, any great difference as to struc- 
ture. But it seems to me impossible to say how many stomachs the 
seal or the pig may be considered as entitled to ; externally, indeed, 
they seem to have but one, internally they present valvular projec- 
tions and a diversified structure, setting at defiance all the usual 
anatomical nomenclature as to this organ. 
Man is considered as having a single stomach ; but this is not 
unfrequently found contracted about the middle, so as to divide the 
cavity, as it were, into two, by means of a narrow contracted por- 
tion. If this be constant during the digestion of the food, as some 
have supposed, we might almost venture to call the human stomach 
double ; but in truth it is not so, and is a phenomenon which takes 
place only occasionally, and in certain individuals: it is a deviation 
from the ordinary human structure, but of the simplest kind, an 
irregularity in man, a regular structure in certain of the lower ani- . 
mals, that structure being, as it is so often, persistent in them, 
whilst in him it is only fugacious. 
Till anatomists have determined what is to constitute a dou- 
ble, what a single stomach, or until they have corrected their no- 
menclature, let us consider the stomach in all animals as a single 
organ, varying with the species, performing a single function, and 
not to be judged of, a priori, by any doctrine, anatomical or phy- 
siological, nor by any pretended necessary relation of dependence 
upon any other co-existing anatomical structures, 
