CONDITIONS MODIFYING INFECTION. 109 



The stomach^ because of its acid reaction, is not a favorable 

 place for the development of bacteria. Sarcinse are frequently 

 found in the stomach, especially during attacks of gastritis; 

 also the bacilli of lactic acid and butyric acid. The Oppler- 

 Boas bacillus is found in carcinoma of the stomach. At one 

 time it was believed to be diagnostic of this condition ; but 

 it is not constant, and is found also in all diseases of the 

 stomach where the conditions are similar to those found in 

 carcinoma. 



The intestinal canal can never be said to be free from bac- 

 teria. Some varieties are constant inhabitants, especially the 

 Bacillus coli communis, the Bacillus lactis aerogenes (in milk- 

 drinkers), and the Streptococcus coli gracilis. These organisms 

 are found more often in the large than in the small bowel. 

 Although the colon bacillus is ordinarily a non-pathogenic 

 organism, it may, under favorable conditions, give rise to 

 very severe and even fatal diarrhoeas. It has frequently been 

 found in suppurative lesions of the intestinal tract and its 

 accessory glands. It is believed to be the cause of ulceration 

 and perforation of the intestine. 



The occurrence of tuberculosis of the mesenteric and retro- 

 peritoneal lymph-glands is evidence of the fact that bacteria 

 can and do pass through the walls of the intestine during 

 health without causing any lesion of the intestine. An en- 

 teritis always predisposes to infection with the Bacillus typho- 

 sus and the cholera spirillum. Infection of the gastro- 

 intestinal tract follows the ingestion of infected food or drink, 

 or the swallowing of tubercular sputum. Occasionally syphi- 

 lis also is transmitted through the gastro-intestinal tract. 



Genito-urinary tract : A few unimportant varieties are found 

 in the acid secretions of the vagina, but this acidity is rather 

 a protection against infection. The uterus is normally free 

 from bacteria. On the external genitals of both man and 

 woman we find pus cocci and the Bacillus smegmatis, which 

 resembles the tubercle bacillus so closely that often it is mis- 

 taken for it. When the urine is examined for tubercle bacilli, 

 this resemblance must not be lost sight of, as the one is sig- 

 nificant of a serious lesion, and the other possesses no patho- 

 logic significance whatever. 



