

STRUCTURE OF THE DIGESTIVE ORGANS. 33 



void a urine which contains a sensible proportion of phosphoric 

 acid. 



7. Special structure of the digestive organs of different 

 animals. 



Animals are beautifully adapted to the conditions in which 

 they are intended to live, and to the food they are most likely 

 to obtain, and most fitted to thrive upon. In so far as they are 

 so fitted by the varied structure of their stomachs, the experi- 

 mental feeder ought to a certain extent to make it a matter of 

 study. 



Purely chemical principles alone are not sufficient to guide 

 the rearer of animals for profit. Chemistry says, give the 

 animal so much protein (gluten, albumen, &c.) every twenty- 

 four hours so much starch or sugar, so much fat, so much of 

 the material of bones, and so much saline matter, and all its 

 wants will be abundantly supplied. But the comparative 

 anatomist, and the animal physiologist, smile at these simple 

 orders. In what form, he asks, must they be given in which of 

 many forms may they be given of all these available forms, 

 which is the best adapted to the structure and functions of the 

 animal's stomach which is likely to produce the most profit- 

 able return? The stomach of man is comparatively simple 

 and one, and his alimentary canal of moderate size and length. 

 The stomach of the horse is also simple or single, and smaller 

 in proportion than that of man ; but his bowels are capacious, 

 showing that he is intended to eat, and therefore requires, food 

 having a certain degree of bulk. " A horse could not live so 

 well on oats, if fed entirely upon them, as when a certain por- 

 tion of fodder is given. With them a certain quantity is required. 

 But this may be carried too far, and the animal may have its 

 bowels loaded with too large a quantity of unnutritious food." 

 (Dick.) The pig's stomach is also simple, and resembles most 

 nearly that of the horse, while its intestines have a nearer 

 resemblance to those of man. 



The ox and sheep have compound stomachs, consisting of 

 four compartments, usually spoken of as the four stomachs. 

 These animals ruminate, or bring up their food from the paunch, 



