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CHAPTER X. 



THE INTESTINAL EXCRETIONS. 



THAT portion of the food which is not taken up by the absor- 

 bents which are everywhere distributed between the stomach 

 and the large intestine is again discharged from the system as 

 faeces. 



The faeces must materially vary with the species of food that 

 is taken, and with the energy of the digestive powers. When we 

 see that many men are kept in a better and more desirable con- 

 dition on a very small quantity of food, than others who take 

 a larger amount of nutritious aliment, we must necessarily 

 conclude that in the former case everything which could possibly 

 serve for nutrition was extracted and suitably employed, while 

 in the latter we must suppose that only a small portion of 

 nutritive matter was taken up from the large quantity of food, 

 and that the greater portion was discharged with the faeces. 

 In accordance with what I briefly stated respecting the fluid 

 secretions of the chylopoietic viscera in relation to the process 

 of digestion, it follows that after food has been taken the faeces 

 must contain (1) that portion of the food which has not been 

 absorbed, and (2) the addition which is received in the form of 

 secretion from the intestinal canal and its appendages, between 

 the mouth and the anus. These consequently are, those sub- 

 stances which are altogether insoluble in the digestive fluids, 

 as for instance, vegetable fibre; those which, although capable 

 of digestion, have from various causes not been digested, as for 

 instance, the flesh of old animals, sinews, ligaments, fat, &c. ; 

 the bile, more or less modified, together with biliphaein and 

 cholesterin, the mucus of the intestinal canal, and a consi- 

 derable amount of salts, amongst which ammoniaco-magnesian 

 phosphate is especially distinguished by its well-defined crystals. 



The faeces of adults are, however, different from those of the 



