V. 

 BACTERIA OF THE STOMACH AND INTESTINE. 



As the secretions of the mouth contain numerous bacteria, these 

 must constantly find their way to the stomach, but conditions are 

 not favorable for their development when the stomach is in a healthy 

 state and its secretions normal. Under certain circumstances, how- 

 ever, there may be an abundant development in the stomach of spe- 

 cies which give rise to various fermentations, and no doubt dyspep- 

 tic symptoms are frequently due to this cause. In the present 

 section we are, however, only concerned with the bacteria of the 

 healthy stomach. Most of these, we think, are to be considered as 

 only temporarily and accidentally present in this viscus as the result 

 of the swallowing of the buccal secretions and of food and drink con- 

 taining them. 



The experiments of Straus and Wiirtz and of others show that 

 normal gastric juice possesses decided germicidal power, which is 

 due to the free hydrochloric acid contained in it. Hamburger (1890) 

 found that gastric juice containing free acid is almost always free 

 from living microorganisms, and that it quickly kills the cholera 

 spirillum and the typhoid bacillus, but has no effect upon anthrax 

 spores. Straus and Wiirtz found that the cholera spirillum is killed 

 by two hours' exposure in gastric juice obtained from dogs, the 

 typhoid bacillus in two to three hours, anthrax bacilli in fifteen to 

 twenty minutes, and the tubercle bacillus in from eighteen to thirty- 

 six hours. The experiments of Kurlow and Wagner, made with 

 gastric juice obtained from the stomach of healthy men by means of 

 a stomach sound, gave the following results : Anthrax bacilli with- 

 out spores failed to grow after exposure to the action of human gas- 

 tric juice for half an hour, but spores were not destroyed in twenty- 

 four hours ; the typhoid bacillus was killed in one hour ; the 

 cholera spirillum, the bacillus of glanders, and Bacillus pyocyanus 

 were all destroyed at the end of half an hour ; the pus cocci showed 

 greater resisting power. Certain bacteria have a greater resisting 

 power for acids than any of those above mentioned, and some of them 

 may consequently pass through the healthy stomach to the intestine 



