INTESTINES IN OUR DOMESTIC ANIMALS. 697 
folds of intestine, and particularly by the sub-sternal muscle (the 
rectus abdominis ), which sustains it during the direct action of these 
parietes in the act of vomition. The esophagus enters the viscus 
perpendicularly, about the middle of its small curvature, almost 
immediately after having passed the right column of the diaphragm. 
At its (terminant) orifice its substance is thick, firm, and white; 
its cavity is completely closed; its mucous lining in folds resem¬ 
bling a radiated flower; but these neither constitute a semilunar 
valve, as Lamorier has said, nor a spiral valve, as Gurlt has in¬ 
sisted. 
In this singular disposition resides the sole cause of the impos¬ 
sibility or extreme difficulty of vomition in solipedes. A good 
idea may be gained of its mode of action by applying to the case 
of the stomach the theory of the hydraulic press. 
Now, let us take the viscus in a state of distention with aliment, 
liquids, and gases, and submit it to the exclusive compression of 
the abdominal muscles (supposing its muscular coat to be paralysed 
through extreme distention). At this moment the cardia is closed, 
and the parietes of the stomach around it perfectly plane; and as 
the pression is according to the law of proportion upon the surface 
which supports it, it must be immensely feeble upon a surface sur¬ 
prisingly small, as represented by the central point of the cardiac 
orifice. Is it not, then, evident that the smallest resistance offered 
by the parietes of the esophagus is sufficient to prevent the dila¬ 
tation of the opening and the escape of alimentous substance I This 
is by no means the case in the omnivora and carnivora, who so 
readily vomit: their esophagus, with its thin walls, terminates in an 
infundibulum where hundred times as much surface is able to resist 
proportional pression, to a degree that cannot be overcome by the 
most energetic contraction. 
The capacity of the stomach, which in most animals is great 
in proportion as that of the intestine is small, is but inconsiderable 
in solipedes in comparison to their size. It would seem as though 
they are designed to derive nourishment from aliments of a much 
more substantial nature than ruminants, and that their digestion 
' no more than commences in their gastric reservoir. 
The capacity varies according to the size of the animal and the 
description of the aliment, as well as probably to several other cir¬ 
cumstances, such as privations, diseases, See. As a minimum, I 
have found it in a very small horse ; and as a maximum, in a horse 
of colossal size. The most ordinary capacity, in subjects of middle 
size, is from 15 to 16 litres. 
The relation existing between the capacity of the stomach and 
that of the intestine is pretty uniform. In a horse of very small 
size it was as 1 to 13; i. e. the capacity of the stomach was thir¬ 
teen times less than that of the intestine. In a second and third 
