GENERAL CHEMICAL COMPOSITION. 205 



struction. Fats, however, are not necessarily present in increased 

 amounts, arid there is no reason to assume that the biliary passages 

 are not patent or that no bile is being secreted. Possibly the lack 

 of color in such stools is referable to the formation of colorless 

 decomposition-products of bilirubin, such as the leuko-urobilin of 

 Nencki, and in the last instance to the presence in the intestinal 

 canal of micro-organisms which are usually absent. Nothing defi- 

 nite is, however, as yet known of the conditions which favor the for- 

 mation of such products. 



Macroscopic Constituents. On macroscopic examination of the 

 feces we frequently find undigested particles of food, such as skins 

 of berries, large pieces of connective tissue, woody vegetable fibres, 

 undigested pieces of apples, pears, potatoes, grains of corn, flakes of 

 casein, etc. 



Microscopic Constituents. On microscopic examination we 

 usually find undigested bits of muscle-fibre, connective- tissue of the 

 white fibrous variety, fragments of the framework of vegetable 

 matter, often still enclosing cells with starch-granules, flakes of 

 casein, globules of fat, fatty acid needles, crystals of calcium oxalate, 

 neutral calcium phosphate, ammonio-magnesium phosphate, calcium 

 lactate (these are seen especially in children on a milk diet), and 

 more rarely of calcium carbonate, calcium sulphate, and cholesterin. 

 So-called Charcot-Leyden crystals, which consist of the phosphate 

 of spermin, are in my experience only found under pathological con- 

 ditions. We further meet with more or less disintegrated epithelial 

 cells, a few leucocytes, bits of mucus, and, above all, with innumer- 

 able micro-organisms. Often, indeed, it appears as though the 

 stools consist of these exclusively. Their number, even in health, 

 is enormous. Sucksdorff thus found in his own person that on an 

 average 53,124,000,000 were eliminated in the twenty-four hours. 



Reaction. In adult man the reaction of the stools is usually 

 alkaline, sometimes neutral, and but rarely acid. Acid stools, on the 

 other hand, are the rule in infants. 



General Chemical Composition. A general idea of the average 

 composition of the human feces may be formed from the following 

 analyses, which are taken from Gautier, and have reference to 1000 

 parts by weight of the fresh material ; 



Adult man. Suckling. 



Water 744.00 871.3 



Solids . . . 267.00 148.7 



Total organic matter 208.75 137.1 l 



Total mineral matter 10.95 2 13.6 



Alimentary residue 84.00 



The organic material yielded : 



Aqueous extract 53.40 53.5 



Alcoholic extract 41.65 8.2 



Ethereal extract 30.70 17.6 3 



1 Including ;~4 parts of mucus, epithelium, and calcareous salts. 



2 Not comprising earthy phosphates. 



3 Of this, :'..'J niirts of cholesterin. 



