456 



THE F^CES IN HEALTH. 



[BOOK II. 



processes of the body, scarcely admits of a doubt. The phenols, the 

 indol, even the foetid skatol, which result from the life-work of the 

 putrefactive bacteria of the intestine, illustrate the general law that 

 the products of living organisms are prejudicial to, and capable of 

 destroying, organisms of the kind which produced them: for all these 

 bodies are antiseptics of more or less power. 



The absorption of the hydrobilirubin, and its subsequent excretion 

 in modified forms in the urine, may be a mere accident of its solu- 

 bility and diffusibility, or it may play a real, though yet undiscovered, 

 part. 



colon. 



SECT. 5. THE KECES IN HEALTH. 



Amount per The weight of the faeces excreted by healthy men 

 amounts, on an average, to one-seventh or one-eighth 

 of that of the solid food, and may be, therefore, estimated as from 

 130 to 200 grms. per diem, but the amount varies remarkably with 

 the nature of the food, with the way in which it has been cooked, or 

 otherwise prepared, &c. When the diet is, in the main, a vegetable 

 one containing much cellulose, the amount of unassimilable matter 

 to be got rid of is much larger than when the diet is mainly an 

 animal one. The quicker, too, the passage of the food through the 

 alimentary canal, i.e. the more rapid the intestinal contractions, the 

 greater, cceteris paribus, the weight of the faeces. 



The consistence of the fasces varies greatly and de- 

 pends, mainly, on the length of sojourn in the colon. 

 The colour is much influenced by the nature of the food, by the 

 abundance or otherwise of the biliary colouring matters and their 

 derivatives, and by the accidental presence of foreign elements, 

 especially of a metallic nature. Thus the faeces passed on a purely 

 animal diet are dark brown, and on a milk diet are yellowish white. 

 When iron and bismuth are present, even in small quantities, in the 

 stools, the colour is a black one, due to the formation of sulphide of 

 iron. After the administration of calomel, the stools have a green 

 colour, which was formerly supposed to be due to an admixture with 

 sulphide of mercury. The true explanation appears, however, to be 

 that under the influence of calomel intestinal putrefaction is arrested 

 and the biliverdin which is derived from the oxidation of the bile 

 colouring matter passes unchanged into the stools. When the bile 

 is cut off from the intestine the stools are clay coloured. 



The amount of solid matters in the faeces varies between 17 '4 

 and 317 p.c. 



The following results were obtained by Bischoff and Voit in the 

 case of carnivores. 



"When fed upon a purely flesh diet a strong dog excreted in 24 hours 

 only 27 40 grms. of faeces containing, on an average, 12-9 grms. of solids, 



