362 VETERINARY PHYSIOLOGY 



constantly being passed onward to the lower part of the 

 large intestine. Here absorption of water leaves a more or 

 less inspissated mass which collects and is periodically 

 voided as the fasces. 



(1) Carnivora. — (a) In fasting animals, faeces are passed at 

 long intervals, and consist of mucin, shed epithelium, the 

 various products of the bile constituents, inorganic salts, and 

 enormous numbers of bacteria. 



(6) In feeding animals the amount and character of the 

 faeces depend largely (1) upon the amount and character of 

 the food ; and (2) upon the bacteria which are growing in the 

 large intestine. If digestion and absorption of food are com- 

 plete, the fasces are the same on different diets, and consist of 

 the intestinal products, which are increased in amount by the 

 stimulating action of the food in the alimentary canal. 



The solids of the fa?ces of a feeding animal consist of 

 the same constituents as the fasces in a fasting animal, with 

 the addition of the undifjested constituents of the food — 

 elastic and white fibrous tissue, remains of muscle fibres, fat, 

 and the earthy soaps of the fatty acids, the fat forming about 

 one-third of the weight of dry f^ces. When a vegetable 

 diet is taken, the cellulose of the vegetable cells, and some- 

 times starch, are present. The cellulose, by stimulating the 

 intestine, is a valuable natural purgative. 



Phosphates, as well as calcium, magnesium, and iron, de- 

 rived from the metabolism of the tissues, are largely excreted 

 into the large intestine, and are passed out in the fseces. 



Probably in an ordinary mixed diet some 80 to 40 per 

 cent, of the phosphorus, about 90 per cent, of the calcium, 

 some 70 per cent, of the magnesium are excreted in the faeces. 



The odour is due to the presence of many different sub- 

 stances, and it varies with the character of the bacterial 

 flora of the large intestine. 



(2) Herbivora. — In these the residual products of digestion 

 are very bulky and evacuation is more frequent than in car- 

 nivora. The horse usually defsecates about ten times a day. 

 The amount passed in twenty-four hours varies with the 

 nature of the food. On an ordinary diet about 15 kilos per 

 diem are passed by the horse, and about 20 by the ox. 



