FECES. 175 



The fecal constituents which at various times and under different 

 conditions may be detected by the use of the microscope are as fol- 

 lows : Constituents derived from the food, such as muscle fibers, 

 connective tissue shreds, starch granules and fat; formed elements 

 derived from the intestinal tract, such as epithelium, erythrocytes 

 and leucocytes; mucus; pus corpuscles; parasites and bacteria. In 

 addition to the constituents named, the following crystalline deposits 

 may be detected : cholesterol, soaps, fatty acid, fat, bismuth sul- 

 phide, hcematoidin, " triple phosphate, }} Char cot-Ley den crystals 

 and the oxalate, carbonate, phosphate, sulphate and lac tat e of cal- 

 cium. 



The detection of minute quantities of blood in the feces (" oc- 

 cult 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 macro- 

 scopical characteristics as well as the microscopical identification 

 through the detection of erythrocytes are both unsatisfactory in 

 their results. Of the tests given for the detection of " occult 

 blood" the aloin-turpentine test (page 178) is 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 these disorders. 



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

 born is sterile. However this condition is quickly altered and bac- 

 teria may be present in the feces before or after the first inges- 

 tion 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 limiting the general infection to the 

 mouth and anus. 



In infants with pronounced constipation two-thirds of the dry 

 substance 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 

 twenty- four hours for an adult is about eight grams. 



Some of the more important organisms met with in the feces are 

 the following : 2 B. coli, B. lactis aero genes, Bact. Welchii, B. 

 bifidus and coccal forms. Of these the first three types mentioned 



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

 matter. This value is, however, probably too high. 



2 Herter and Kendall : Journal of Biological Chemistry, 1908, V, p. 283. 



