284: COMPOSITION OF THE FAECES. 



The odour, which is stronger after a flesh diet than after a vegetable diet, is 

 caused by some faecal products of putrefaction, which have not yet been isolated ; 

 also by volatile fatty acids and by sulphuretted hydrogen, when it is present. 



The colour of the faeces depends upon the amount of altered bile-pigments 

 mixed with them, whereby a bright yellow to a dark brown colour is obtained. 



The colour of the food is also of importance. If much blood be present in the food, the 

 faeces are almost brownish-black from haematin ; green vegetables = brownish-green from 

 chlorophyll ; bones (dog) = white from the amount of lime ; preparations of iron = black from 

 the formation of sulphide of iron. 



The faeces contain 



(1) The unchanged residue of animal or vegetable tissues used as food ; hairs, 

 horny and elastic tissues; most of the cellulose, woody fibres, spiral vessels of 

 vegetable cells, gums. 



(2) Portions of digestible substances, especially when these have been taken in 

 too large amount, or when they have not been sufficiently broken up by chewing. 

 Portions of muscular fibres, ham, tendon, cartilage, particles of fat, coagulated 

 albumin vegetable cells from potatoes, and other vegetables, raw starch, &c. 



All food yields a certain amount of residue white bread, 3 '7 per cent.; rice, 4*1 per cent. ; 

 flesh, 47 per cent. ; potatoes, 9*4 per cent. ; cabbage, 14*9 per cent. ; black bread, 15 per cent. ; 

 yellow turnip, 207 per cent. (Rubncr). 



(3) The decomposition-products of the bile-pigments, which do not now give 

 Gmelin's reaction j as well as the altered bile-acids ( 177, 2). This reaction, 

 however, may be obtained in pathological stools, especially in those of a green 

 colour; unaltered bilirubin, biliverdin, glycocholic and taurocholic acids occur 

 in meconium ( 182). 



[MacMunn found no unchanged bile-pigments in the foaces. A substance called stercobilin is 

 obtained from the faeces, and it closely resembles what has been called "febrile" urobilin, but 

 it is certainly different from normal urobilin.] 



(4) Unchanged mucin and nuclein the latter occasionally after a diet of bread, 

 together with partially disintegrated cylindrical epithelium from the intestinal 

 canal, and occasionally drops of oil. Cholesterin is very rare. [Ten grains of a 

 substance, stercorin, said to be a modification of cholesterin, occur in the faeces, 

 (Flint).'] The less the mucus is mixed with the faeces, the lower the part of the 

 intestine from which it was derived (Nothnagel). 



(5) After a milk diet, and also after a fatty diet, crystalline needles of lime com- 

 bined with fatty acids and chalk soaps constantly occur, even in sucklings ( Weg- 

 seheider). Even unchanged masses of casein and fat occur during the milk cure. 

 Compounds of ammonia, with the acids mentioned as the result of putrefaction 

 ( 184, III.), belong to the faecal matters (Brieger). 



(6) Amongst inorganic residues, soluble salts rarely occur in the faeces because 

 they diffuse readily, e.g., common salt, and the other alkaline chlorides, the compounds 

 of phosphoric acid, and some of those of sulphuric acid. The insoluble compounds 

 of which ammoniaco-magnesic or triple phosphate, neutral calcic phosphate, yellow 

 coloured lime salts, calcium carbonate, and magnesium phosphate are the chief, 

 form 70 per cent, of the ash. Some of these insoluble substances are derived from 

 the food, as lime from bones, and in part they are excreted after the food has been 

 digested, as ashes are eliminated from food which has been burned. 



Concretions. The excretion of inorganic substances is sometimes so great, that they form 

 incrustations around other faecal matters. Usually ammoniaco-magnesic phosphate occurs in 

 large crystals by itself, or it may be mixed with magnesium phosphate. 



(7) Micro-organisms. A considerable portion of normal faecal matter consists 

 of micrococci and microbacteria, yeast is seldom absent (Frerichs, Nothnagel). 



To isolate the individual fungi, Escherich has made pure cultivations from the intestinal 

 contents of sucklings, and Bienstock from adults. In the intestine of sucklings which 

 have been nourished entirely on their mother's milk, the Bacterium lactis aerogenes (fig. 205, 2) 



