THE ABSORPTION OF THE REDUCED FOODSTUFFS 1035 



C. THE FORMATION OF THE FECES ^ 



Character of the Feces. — ^The feces are alkaline in their reaction, 

 and contain the indigestible constituents of the food plus a very small 

 proportion of nutritive material which has escaped digestion, epithelial 

 cells, pigment, mucin, and countless bacteria. The products of bac- 

 terial decomposition, include indol and scatol to which their disagree- 

 able odor is due, and also certain gases, such as NH4, CO2, H, Nand 

 H2S. A small quantity of fecal material is also excreted during 

 periods of starvation, as well as from isolated loops of intestine. In the 

 latter case, however, it consists solely of desquamated epithelium, 

 intestinal juice, and bacteria; simulating, therefore, the meconium of 

 the new-born child which embraces solely concentrated bile and cast- 

 off epithelium. The character of the feces of a normal adult depends 

 in a large measure upon the type of the food ingested. They contain 

 elastic fibers, and the remnants of the connective tissues, spiral ves- 

 sels of plants, and vegetable residue in the form of cellulose. When 

 no vegetables have been ingested, about 65 to 75 per cent, of the feces 

 consist of water, while their dry residue contains about 7 per cent, of 

 nitrogenous material. Their non-nitrogenous portion is composed 

 of about 11 to 12 per cent, of ash and 12 to 18 per cent, of substances 

 soluble in ether, as well as of sterobilin and other bile residues. The 

 ethereal extract embraces fatty acids, cholesterol, a small amount 

 of lecithin, and neutral fat. The proteins consist of mucin and nucleo- 

 protein, derived from the epithelial cells and the countless numbers of 

 bacteria. The ash embodies chiefly calcium phosphate and small 

 amounts of iron and magnesium. 



Very different conditions are met with if " the diet contains large 

 amounts of cellulose, because this material escapes from the small 

 intestine unchanged and may carry other substances with it. In 

 the large intestine, it is first acted upon in a slight measure by bacteria 

 before it actually becomes a constituent of the feces. Thus, Voit has 

 shown that as much as 42 per cent, of the nitrogen of the food of vege- 

 tarians may be lost to the system, obviously because the digestive 

 juices cannot penetrate its cellulose investments. Only about 85 per 

 cent, of the dry substance of green vegetables is available for absorp- 

 tion, and only 80 per cent, of carrots and turnips. But naturally, the 

 vegetable proteins as such are as digestible as the animal proteins, 

 and their complete utilization requires merely maceration and cooking 

 to free them from the cellulose. In the herbivora, of course, condi- 

 tions are quite different, because in them the beginning portion of the 

 large intestine is set aside especially for the digestion by fermentation 

 of these particular types of foods. This material may remain here 

 for two or three days, while it undergoes slow reduction and absorption. 



Botulism. — Excessive protein putrefaction in the intestine may 

 give rise to a complex of symptoms, consisting of constipation, vertigo, 

 diplopia, hemianopia, difficulty in swallowing, weakness, and cardiac 



