QUALITATIVE BACTERIOLOGICAL ANALYSIS. 251 



The remaining cultures out of the total thirty- two isolated 

 showed extreme variability. Side by side with vibrios which 

 liquefied gelatine in a manner absolutely characteristic of the 

 true cholera spirillum, others were found which liquefied gelatine 

 very slightly, or not at all, and which multiplied with great 

 difficulty. Many also refused to grow on ordinary gelatine, and 

 also in broth, except at the room temperature. It could not be 

 said that the failure to develop at 37 C. was directly related to 

 a condition of degeneration, for many vibrios which failed to 

 liquefy gelatine grew at 37, and vice versa; many which liquefied 

 gelatine failed to grow at 37 C. The cultures on potato failed 

 to be of use as a means of diagnosis. With regard to the 

 nitroso-indol reaction, all the vibrios isolated from water were 

 able to produce indol, but very few of them at the same time 

 were able to reduce nitrates to nitrites. As regards pathogenicity, 

 only four out of the thirty-two microbes were found to be patho- 

 genic when injected intra-peritoneally into guinea-pigs; but 

 many of them, though they did not cause immediate lethal 

 effects, produced a condition of gradual wasting from which the 

 animals eventually died. It was also found that if 1 c.c. of a 

 sterilised culture of B. coli was injected into the peritoneum of 

 a guinea-pig, and a small quantity of these vibrios at the same 

 time into the pleura of the animal, the vibrios multiplied and 

 caused the death of the animal. Sanarelli then endeavoured to 

 find out whether there was any reciprocal reaction between 

 animals vaccinated with the four pathogenic water vibrios and 

 two other vibrios derived from undoubted cases of cholera. 

 Guinea-pigs were vaccinated with cultures grown for eight to 

 ten days in peptone-gelatine and then sterilised at 120. A 

 successful vaccination was proved by the animal resisting a fatal 

 dose of the active culture. The results of the experiments are 

 shown in the following table. The sign + indicates that the 

 guinea-pig, vaccinated against a given variety, survived after 

 inoculation with a different variety ; the sign indicates the 

 death of the vaccinated animal. Sanarelli does not state in his 

 paper whether the cultures used for vaccination were sterilised 

 at 120 C. or 120 F. If the former temperature was used, the 

 cultures would not be likely to have much protective influence. 



