COMPOSITION OF F^CES. 445 



Of the feeds examined in per cent, of digestibility of the albumi- 

 noids, bean-meal stands the highest, linseed-meal (old process) next, and 

 pea-meal but little less, while the mixed hay of rather inferior quality, 

 but similar to much hay feed, stands lowest. The old process linseed- 

 meal shows a higher per cent, of digestibility than the new process ; this 

 difference is due, very likely, to the partial cooking of the meal by steam 

 during the process of oil extraction and preparation of the meal for feed. 

 Cotton-seed meal, much the richest substance examined, gives a high 

 co-efficient for digestibilit} r . A marked difference exists between the 

 first three hays, showing plainly the difference between well-cured hay 

 and that exposed to the weather. 



Of the raw and cooked foods examined, in every instance the higher 

 digestion co-efficients were obtained from the raw foods, and an exami- 

 nation of the table of anatyses shows an actual loss in albuminoids by 

 cooking, and a change in the fat rendering it insoluble in ether, and un- 

 acted upon by acids or alkalies of the strength used for fibre determina- 

 tions. 



XII. THE COMPOSITION OF F^CES. 



The faeces are composed of the more or less altered residue of the 

 food-stuffs, to which are added the excretory products of the digestive 

 tract. The character of the faeces will be governed by the relative 

 amounts of these two groups of substances. 



When no food is given, as during fasting and in the fetal state, the 

 faeces consist only of the excretory products of the digestive tract. This 

 state of affairs will also hold when the food given is entirely digested 

 and absorbed, as is the case with the dog fed on a not too abundant 

 meat diet. 



The amount of matter found in the faeces which fs not derived from 

 the faeces may vary under different circumstances. In the fasting con- 

 dition, according to F. Mu'ller, the faeces contain 4 per cent, of the total 

 amount of nitrogen eliminated, 1.4 per cent, of the amount of carbon, and 

 25 per cent, of tbe inorganic matter. When, however, food is given, the 

 activity of the intestinal mucous membrane i* increased, and through 

 increased secretion and excretion the percentage of faecal constituents 

 not derived from the food is increased. 



The faeces passed in the fasting condition furnish, therefore, no index 

 as to the degree of intestinal excretion. This, however, may be reached 

 through the examination of the faeces of eamivora fed on meat, when 

 the amount of nitrogen eliminated will toe- afeowt 1,2 per cent, of the total 

 amount, carbon 2.7 per cent., and inorganic matters 18.5 per cent. 



Meconium, or the contents of the foetal intestinal canal, contains 

 neutral fats, free fatty acids, biliverdin,bilirubin, unchanged biliary acids, 



