508 PATHOGENIC SPIRILLA. 



cholera. Moreover, it has been shown by experiment that this spi- 

 rillum is very sensitive to the action of acids, and is quickly de- 

 stroyed by the acid secretions of the stomach, of man or the lower 

 animals, when the functions of this organ are normally performed. 

 By a special method of procedure, however, Nicati and Rietsch, and 

 Koch, have succeeded in producing in guinea-pigs choleraic symp- 

 toms and death. The first-named investigators injected cultures of 

 the spirillum into the duodenum, after first ligating the biliary duct; 

 the animals experimented upon died, and the intestinal contents con- 

 tained the spirillum in large numbers. The fact that this procedure 

 involves a serious operation which alone might be fatal, detracts 

 from the value of the results obtained. Koch's experiments on 

 guinea-pigs are more satisfactory, and, having been fully controlled 

 by comparative experiments, show that the ' ' comma bacillus " is 

 pathogenic for these animals when introduced in a living condition 

 into the intestine. This was accomplished by first neutralizing the 

 contents of the stomach with a solution of carbonate of soda five 

 cubic centimetres of a five-per-cent solution, injected into the stomach 

 through a pharyngeal catheter. For the purpose of restraining in- 

 testinal peristalsis the animal also receives, in the cavity of the abdo- 

 men, a tolerably large dose of laudanum one gramme tincture of 

 opium to two hundred grammes of body weight. The animals are 

 completely narcotized by this dose for about half an hour, but re- 

 cover from it without showing any ill effects. Soon after the ad- 

 ministration of the opium a bouillon culture of the cholera spirillum 

 is injected into the stomach through a pharyngeal catheter. As a 

 result of this procedure the animal shows an indisposition to eat and 

 other signs of sickness, its posterior extremities become weak and 

 apparently paralyzed, and, as a rule, death occurs within forty-eight 

 hours. At the autopsy the small intestine is found to be congested 

 and is filled with a watery fluid containing the spirillum in great 

 numbers. Comparatively large quantities of a pure culture injected 

 into the abdominal cavity of rabbits or of mice often produce a fatal 

 result within two or three hours ; and Nicati and Rietsch have ob- 

 tained experimental evidence of the pathogenic power of filtered cul- 

 tures not less than eight days old. The most satisfactory evidence 

 that this spirillum is able to produce cholera in man is afforded by an 

 accidental infection which occurred in Berlin (1884), in the case of a 

 young man who was one of the attendants at the Imperial Board of 

 Health when cholera cultures were being made for the instruction of 

 students. Through some neglect the spirillum appears to have been 

 introduced into his intestine, for he suffered a typical attack of 

 cholera, attended by thirst, frequent watery discharges, cramps in 

 the extremities, and partial suppression of urine. Fortunately he 



