SUMMABY. 403 



digestion. If an animal be kept for some days without food-, 

 cholesterine will be found in the faeces, though for a few 

 days stercorine is also present. It is generally recognized by 

 those who have analyzed the faeces, that cholesterine does 

 not exist in the normal evacuations ; but whenever digestion 

 is arrested, the bile being constantly discharged into the 

 duodenum, cholesterine is found in large quantity. For ex- 

 ample, in hibernating animals, cholesterine is always present 

 in the faeces. 1 The same is true of the contents of the intes- 

 tines during foetal life ; the meconium always containing a 

 large quantity of cholesterine, which disappears from the 

 evacuations when the digestive function becomes established. 



Summary. The entire quantity of faeces passed in the 

 twenty-four hours is from four to seven ounces. The color 

 may be of any shade between a yellow, a yellowish-brown, 

 and a very dark brown. The odor of the faeces is sui generis, 

 and is developed only after the matters have been discharged 

 by the ileum into the large intestine. 



The reaction of the faeces may be alkaline, neutral, or 

 acid ; depending, probably, upon changes which take place 

 in the undigested residue of the food. 



The proportion of solid residue in the faeces after evapo- 

 ration is about two hundred and seventy parts per thousand. 

 The absolute quantity of solid matter discharged in the faeces 

 in the twenty-four hours is about four hundred and sixty 

 grains ; only about ten per cent, of which consists of undi- 

 gested matters. 



The matters contained in the faeces which are derived 

 from the food consist largely of vegetable structures, such as 

 cellulose, spiral vessels, the cortex of grains, etc. The mat- 

 ters derived from animal food are, pieces of tendinous or 

 elastic structure, ill-defined grumous matter, particles of mus- 

 cular tissue in various stages of disintegration, the inor- 



1 MARCET, op. dt., Philosophical Transactions, London, 1854, p. 278 . 



