THE BACTERIA OF THE NORMAL HUMAN BODY. I43 



The smegma of the external genitals contains numerous 

 bacteria, among which are frequently found bacilli which 

 retain their color after treatment with acids in the Gabbett 

 method for staining tubercle bacilli. It is uncertain whether 

 these bacilli form a special group of organisms by themselves, 

 having as one of their properties the power of retaining the stain 

 after acids, or whether they are bacilh of no particular sort, which 

 resist acids after staining owing to the oily material with which 

 they have been impregnated in this pecuHar secretion. These 

 organisms must be taken into account in staining for tubercle 

 bacilli, urine or other secretions which might accidentally con- 

 tain particles of smegma. Usually the employment of alcohol 

 after the acid will remove the color from the smegma bacilli 

 (Hueppe). Sometimes smegma bacilli are as resistant as 

 tubercle bacilli to decolorizing agents (Welch); see page 33. 

 Similar acid-proof bacilli occur about the genitals of the domestic 

 animals.* 



The bacteria of the stomach and intestines are of great 

 interest and importance. The alimentary tract of new-born 

 infants and the meconium are sterile. In from four to eighteen 

 hours organisms begin to appear. They may enter either from 

 the mouth or the anus. There seems to be no constancy in the 

 nature of the forms which are found at first, but their character 

 depends upon the surroundings. 



The bacterial inhabitants of the stomach are less constant 

 than we shall find those of the intestines to be. Under normal 

 circumstances they seem to be those introduced from the mouth. 

 Different investigators, at all events, have met with quite differ- 

 ent species. It appears that the hydrochloric acid (about 2 

 parts per thousand) present in the gastric juice at the height 

 of digestion possesses decided germicidal properties. This 

 germicidal power exercises a restraining influence upon fer- 



* Cowie. Journal Experimental Medicine. Vol. V., p. 205. 



