144 BACTERIOLOGY 



During the progress of the disease the bacilli are found 

 principally in the mucous membrane and contents of the 

 intestinal canal, but not in the blood. 



To examine cholera stools for bacilli, the evacuation is 

 mixed with an equal bulk of alkaline meat -bouillon and let 

 stand in an open glass for twelve hours at a temperature of 

 30 to 40 C. An abundant development on the surface 

 results, and preparations are obtained by this method of in- 

 vestigation which consist of cholera bacilli only. To re- 

 cognise the presence of the bacilli even without the micro- 

 scope, a good way is to add 10 per cent, hydrochloric acid, 

 which after only a few minutes stains the cholera cultures 



a rose-violet colour, forming 

 the cholera reaction. 



The introduction of pure 

 cultures in bouillon into the 

 stomach of guinea-pigs re- 

 sulted in Koch's hands in an 

 unmistakable infection, when 



FIG. 51. FINKLER-PRIOR BACILLI FROM A Combined with the admillis- 

 PURE CULTURE. (After Jaksch.) 



tration of sodium bicarbonate 



and opium. To avoid the detrimental action of the gastric 

 juice, and at the same time to diminish intestinal peri- 

 stalsis, Nicati and Eietsch ligatured the ductus choledochus 

 and made the injection directly into the duodenum. Intro- 

 duction of cholera cultures into the circulation also causes 

 the death of the animals, and in that case the bacilli can 

 be detected in all the organs. 



The problem frequently arises, to determine with cer- 

 tainty whether in a given case it is the bacilli of cholera 

 Asiatica that have to be dealt with, or other micro-organ- 

 isms resembling them in form. One of these is the Vibrio 

 proteus, which was discovered by Tinkler and Prior in the 

 evacuations of persons suffering from cholera nostras, and 



