228 PHYSIOLOGICAL CHEMISTRY 



phate," Char cot-Ley den crystals, and the oxalate, carbonate, phosphate, 

 sulphate, and lactate of calcium. (See Figs. 70 to 75, pp. 233 and 234.) 

 The koprosterol of the feces is similar to cholesterol, and may be 

 formed by the reduction of the latter. It responds to cholesterol color 

 tests and has the same solubility, but possesses a lower melting-point and 

 crystallizes in fine needles instead of plates such as cholesterol forms. 



The detection of minute quantities of blood in the feces ("occult 

 blood") has recently become a recognized aid to a correct diagnosis of 

 certain disorders. In these instances the hemorrhage is ordinarily so 

 slight that the identification by means of macroscopical characteristics 

 as well as the microscopical identification through the detection of ery- 

 throcytes are both unsatisfactory in their results. Of the tests given 

 for the detection of " occult blood" the benzidine reaction, Lyle-Cuft- 

 man guaiac procedure and the hematein tests (page 

 238) are probably the most satisfactory. Since 

 " occult blood" occurs with considerable regularity 

 and frequency in gastrointestinal cancer and in 

 gastric and duodenal ulcer, its detection in the feces 

 is of especial value as an aid to a correct diagnosis of 



FIG. 68. CHARCOT- these disorders. Certain precautions are essential. 

 LEYDF.N CRYSTALS. , ., A , ,. , P . .. 



such as the establishment of a meat-free diet over a 



period of time before the specimen is collected. (Feces from a meat 

 diet will give an occult blood reaction with some of the most delicate 

 tests.) Bleeding from the bowel such as is seen in hemorrhoids, as 

 well as the admixture of menstrual blood, is to be considered in the 

 interpretation of the result. 



It has been, quite clearly shown that the intestine of the newly born 

 is sterile. However, this condition is quickly altered and bacteria may 

 be present in the feces before or after the first ingestion of food. There 

 are three possible means of infecting the intestine, i.e., by way of the 

 mouth or anus or through the blood. The infection by means of the 

 blood seldom occurs except under pathological conditions, thus limit- 

 ing the general infection to the mouth and anus. 



In infants with pronounced constipation two-thirds of the dry sub- 

 stance of the stools has been found to consist of bacteria. In the stools 

 of normal adults probably about one-third of the dry substance is 

 bacteria. 1 The average excretion of dry bacteria in 24 hours for an 

 adult is about 8 grams. The output of fecal bacteria has been found 

 to undergo a decrease under the influence of water drinking with meals. 2 



1 Schittenhelm and Tollens found bacteria to comprise 42 per cent of the dry matter. 

 This value is, however, undoubtedly too high. 



2 Mattill and Hawk: Jour. Am. Chem. Soc., 33, 1999, 1911; Blatherwick and Hawk: 

 Bioch. Bull.; 3, 28, 1913. 



