DUODENAL DIGESTION IN THE HORSE. 121 



size ; while in the ilium they become by degrees shorter, 

 smaller, and fewer. 



Duodenal Digestion. The food of the ox, like that of 

 similar animals, contains proximate chemical principles de- 

 rived from the vegetable kingdom, some of which are capable 

 of augmenting the organism of the animal frame, and repair- 

 ing the waste which it is unceasingly undergoing during the 

 various acts of life. Others are incapable of repairing this 

 waste, yet serve, by their slow combustion during the act of 

 respiration, to maintain the temperature of the animal in a 

 medium which, being almost always much below the standard 

 animal temperature, is continually abstracting heat therefrom. 

 The proximate principles which can augment and repair the 

 animal organism are albumen, fibrine, and caseine ; those which 

 cannot produce this effect, but serve to maintain temperature, 

 are principally starch, sugar, and oil. While, however, it must 

 be acknowledged that such substances as starch, sugar, and oil, 

 do not enter into the composition of the principal solids of the 

 living body as essential constituents, yet, as respects oil in par- 

 ticular, it must be borne in mind that, though in the semi-fluid 

 state during life, it is contained in a sufficiently firm series 

 of membranous cells so that, in effect, it does act the part of 

 a solid. In such circumstances it obviously belongs, like the 

 bones, to the passive organs of locomotion. In the feeding 

 of cattle for food, fat or oil holds so prominent a place that 

 no circumstance discoverable respecting it, whether hitherto 

 explained or still inexplicable, is to be neglected or left out 

 of view. There is one fact respecting oil or fat as an aliment, 

 which physiology has not yet placed in a sufficiently clear 

 light. The lacteal absorbents arising from the upper part of 

 the small intestines become opaque, owing to the presence of 

 chyle, some time after a meal. This opacity is due, so it is 

 taught, to the presence of fatty corpuscles : here, then, a ques- 



