438 A MANUAL OF BACTERIOLOGY 



water ; milk, salads, vegetables and flies are other 

 sources of infection. The organism has been found in 

 the dejecta of contacts not suffering from the disease, and 

 it may sometimes persist for long periods after convales- 

 cence. In these cases the vibrio may sometimes be located 

 in the biliary tract. Crendiropoulo examined the stools 

 of 34,461 persons on ships coming from cholera-infected 

 ports. Cultures of vibrios were obtained from 63 of these, 

 of which 23 were agglutinated, and 40 were not agglu- 

 tinated, by a high-titre cholera serum. 



The relation of the cholera vibrio to the disease has 

 been a very vexed question in the past, but the outcome 

 of the voluminous researches which have been made is 

 to confirm Koch's work. The organism is found in all 

 cases of cholera, and several instances of laboratory 

 infection from cultures have been recorded. 



None of the lower animals suffers from or contracts a 

 disease in any way comparable to Asiatic cholera, so that 

 the test of animal experiments cannot be applied except 

 in the case of young suckling rabbits (see below, " Anti- 

 serum "). By first neutralising the acidity of the gastric 

 juice by an injection of sodium carbonate solution into 

 the stomach, then diminishing peristalsis by an injection 

 of tincture of opium into the peritoneal cavity, and finally 

 injecting a broth culture of the cholera vibrio into the 

 stomach, Koch succeeded in inducing in guinea-pigs a 

 condition somewhat similar to cholera in man namely, 

 indisposition with falling temperature, weakness of the 

 extremities, and death in forty-eight hours. Post mortem, 

 the small intestine was congested and filled with a watery 

 fluid containing large numbers of the vibrios. Injected 

 into the peritoneal cavity of mice, guinea-pigs and rabbits, 

 the vibrio produces death from a general septicffimia, and 

 intra-muscular inoculation into pigeons is sometimes fatal. 

 The virulence varies much and is lost under cultivation. 



