S8 



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 tlie 

 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 vascular, 

 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 is not by an insensible, but by a sudden 

 transition that the lining membrane of the stomach is thus divided into two 

 portions. The right 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 

 strttcf teres and fii?tctwm oi OYg^crasms; 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. 



