QUALITATIVE BACTERIOLOGICAL ANALYSIS. 26\S 



Cholera Vibrios and B. Acidi Lactici. When grown in a 

 medium free from sugar the B. acidi lactici had no influence on 

 the vibrios ; but in milk, owing to the production of lactic acid, 

 the vibrios quickly died out. 



Cholera Vibrios and B. Cyanogenus. There was no unfavour- 

 able influence ; both bacteria grew well together. 



Cholera Vibrios and Red, White, and Orange Cocci from 

 Air. The vibrios gained the upper hand and the cocci 

 disappeared in a month. The yellow sarcina behaved in the 

 same manner. Three yeasts were also destroyed in a short 

 time. 



Bacilli isolated from faeces, singly and combined, were found 

 to have no prejudicial influence on the cholera vibrios. 



Kitasato also investigated the growth of cholera vibrios in 

 sterilised cultures of a large number of bacteria, and found that 

 if the cultures were recent the vibrios grew well, but the older 

 the cultures the more feeble was the development of the vibrios. 

 In pyocyaneus cultures, however, the vibrios always died out. 



THE BEHAVIOUR. OF THE SPIRILLUM OF ASIATIC: CHOLERA ix 

 NUTRIENT MEDIA CONTAINING ACIDS AND ALKALIES. 



This subject has been studied by Kitasato, who employed the 

 same methods as were used for his studies of the growth of the 

 B. typhosus in acid and alkaline media. The results obtained 

 are shown on the following page : 



Kitasato found that in acid media the growth of the cholera 

 vibrios was dependent on the temperature. When he added 

 to neutral agar media 0'225 per cent, lactic acid, and then 

 inoculated the media with cholera vibrios, no growth occurred 

 if the plates were kept at 20 to 22 C., but if the plates were 

 incubated at 37 C. colonies developed in three days. 



The same result is seen when cholera vibrios are planted out 

 on slightly acid potatoes ; no growth occurs at 22 C., but at 

 37 C. the characteristic development takes place. 



Liborius found that 0*0246 per cent, caustic lime destroyed 

 cholera vibrios. Kitasato^s higher figure was due to the fact 

 that he employed undiluted broth, and some of the lime was 

 expended in neutralising the phosphates contained in the 

 broth. 



