498 DIGESTION. 



division of the various bacteria occurs in dogs in the different parts of the 

 intestine and certain varieties of bacteria occur in greater quantities than 

 others, according to the kind of food taken. Perhaps, also, agreeing 

 with the .experience of CONRADI and KuRpjuwEiT, 1 the toxines pro- 

 duced by the intestinal bacteria may, by their antiseptic action, keep 

 the putrefactive processes in the intestine within bounds. 



Feces. It is evident that the residue which remains after com- 

 plete digestion and absorption in the intestine must be different, both 

 qualitatively and quantitatively, according to the variety and quantity 

 of the food. In man the quantity of excrement from a mixed diet 

 is 120-150 grams, with 30-37 grams of solids, per twenty-four hours, 

 while the quantity from a vegetable diet, according to VoiT, 2 was 333 

 grams, with 75 grams of solids. With a strictly meat diet the excre- 

 ment is scanty, pitch -like, and black. The scanty feces in starva- 

 tion has a similar appearance. A large quantity of coarse bread yields 

 a great amount of light-colored excrement. In these cases the feces 

 are also habitually poorer in nitrogen than after food rich in protein. 

 The individuality also plays an important role in the utility of the food 

 and the formation of feces (SCHIERBECK 3 ) . If there is a large propor- 

 tion of fat, it takes a lighter clay-like appearance. The decomposi- 

 tion products of the bile-pigments seem to play only a small part in the 

 normal color of the feces. 



The constituents of the feces are of different kinds. In the excre- 

 ment are found digestible or absorbable constituents of the food, such as 

 muscle fibres, connective tissues, lumps of casein, grains of starch, and 

 fat, which have not had sufficient time to be completely digested or 

 absorbed in the intestinal tract. In addition the excrement contains 

 indigestible bodies, such as the remains of plants, keratin substances, 

 and others ; also form-elements originating from the mucous coat and the 

 glands; constituents of the different secretions, such as mucin, cholic 

 acid, dyslysine, and cholesterin (koprosterin or stercorin), purine bases,* 

 and enzymes; mineral bodies of the food and the secretions; and, lastly, 

 products of putrefaction or of digestion, such as skatol, indol, volatile 

 fatty acids, purine bases, lime, and magnesia soaps. Occasionally, also, 

 parasites of different kinds occur; and lastly, the excrement contains 

 micro-organisms of various species. 



1 Bienstock, Arch. f. Hygiene, 39; Horowitz, Zeitschr. f. physiol. Chem., 52; Conradi 

 and Kurpjuweit, Munch, med. Wochenschr., 1905. 



2 Zeitschr. f . Biologic, 25, 264. 



3 Arch. f. Hygiene, 51. 



4 In regard to the purine bases in feces, see Hall, Journ. of Path, and Bacteriol., 9; 

 Schittenhelm, Arch. f. klin. Med., 81; Schittenhelm and Kriiger, Zeitschr. f. physioh 

 Chem., 45. 



