252 DIGESTIVE SYSTEM. 



preventing the escape or expulsion from the stomach of any 

 crude or indigested aUment — of solid matters that have not 

 been duly softened and dissolved — into the intestinal canal : I 

 say solid matters, for fluids pass freely through it at all times 

 into the intestines, without detention in the stomach. Actual 

 experiment evinces that they do ; but we may also satisfy our- 

 selves of this fact by contrasting the quantity of water a horse 

 that is thirsty will lake at a single draught with the known 

 capacity of his stomach. 



Cuticular. — The stomach of the horse-species differs remarkably 

 from that, I believe, of all other quadrupeds, with the exception 

 of the graminivorous moiiogastric, in having a partial cuticula?- 

 lining, that maybe reckoned as a third coat: by turning the 

 viscus inside out, or by slitting it open along its great curvature, 

 this part, so conspicuous for its white and wrinkled surface, will 

 be broadly exposed to view. And now we can trace its well- 

 defined border, forming the boundary line between it and the 

 other internal coat, the course of which is waving or serpentine, 

 something like the figure of an S. This lining extends over the 

 cul-de-sac or left extremity of the stomach, covering not quite 

 one-half of its entire internal surface. We commonly find it 

 thrown into wrinkles, technically termed rugce, which in some 

 are so disposed as to form a sort of net-work ; a condition that 

 is owing to its not being possessed of sufficient elasticity to ac- 

 commodate itself to the varying capacity of the organ. This 

 cuticular substance is of the same nature as the lining of the 

 esophagus, with which, indeed, at the cardia it is continuous. 

 Numerous small openings are visible upon its inner surface, 

 through which issues a mucous fluid, the product of follicular 

 glands underneath, which serves a use in the digestive process. 



The fourth^ mucous, villous, or other internal coat, extends 

 over that part of the stomach left unoccupied by the cuticular. 

 Its surface is of a yellowish cast, inclining in places to a red. 

 It is soft, fine, and cellular in its texture, and possesses con- 

 siderable vascularity. When closely and attentively examined, 

 it is found to present inwardly numerous little ragged or shaggy 

 processes, which, from their giving it the appearance of velvet, 

 have received the name of villi : hence the epithet, villous. They 

 appear to be composed principally of the minute ramifications of 

 those bloodvessels which we believe to perform the office of the 

 gastric secretion : by some the villi are supposed to have numer- 

 ous minute glands in their composition ; but, in point of fact, we 

 do not know precisely what is their intimate structure*. This 



* Some persons say that the follicles upon the internal coat are for the 

 purpose of secreting mucus; others, that they prepare the gastric fluid. 



