58 
Outside, the stomach is seen to be of uniform appearance; but if the 
interior is opened, one is at first struck by the different aspect, which its 
lining membrane presents, according as it is examined on the right, or on the 
left side. To the left it has all the characters of the lining of the gullet, in being 
white, harsh, and even resisting ; and it is covered by a thick layer of cells, 
called epithelial. To the right it is thick, wrinkled, spongy, very vasculai, 
and has a reddish-brown tint, which is speckled by darker patches. Here it 
loses its harsh consistency, and is deprived of the remarkably thick epithelial 
covering which it exhibits on the left side, being covered by a very thin layer 
of epithelial cellular structure. It isnot by an insensible, but by a sudden 
transition that the lining membrane of the stomach is thus divided into two 
portions. The tight part constitutes the true stomach of the horse, as on it 
alone devolves the secreting function, and the elaboration of the “gastric 
juice,” the fluid which digests the food. The left part is considered to be a 
dilatation of the gullet (Chauveau). The accompanying picture shows this- 
arrangement of the interior of the horse’s stomach, from Chauveau’s anatomy 
(for the English translation of which we are indebted to Dr. Fleming, 
LL.D., F.R.C.V.S.) 
In the wild condition, the horse lived on the grass of the field; and the 
smallness of the stomach, is in itself sufficient evidence that the organ is 
so constituted as to require to be frequently replenished in order to duly 
nourish the animal. 
We have heard a great deal of Mr. Darwin’s theory, and the theory of 
evolution generally, of late years, and we learn from it that “the changing 
conditions of the environment must produce corresponding changes in the 
structures and functions of organisms; and there is supplied in the variability 
of species a safety valve by which organisms which can most completely 
adapt themselves to the changed conditions are far more likely to survive 
and prosper than others less capable.” (G. Gresswell, on the Evolution 
hypothesis.) Under domestication the conditions of life of the horse are 
necessarily changed. The main bulk of his food is given to him dry, and 
