QUALITATIVE BACTERIOLOGICAL ANALYSIS. 261 



had been grown, was not a favourable medium for many 

 bacteria. 



Kitasato made numerous experiments with cholera vibrios and 

 pathogenic and non-pathogenic bacteria. The methods em- 

 ployed were as follows : 



(1) The cholera vibrio and the organism selected were planted 

 out in parallel streaks, and in the form of a cross, on gelatine 

 plates. 



(2) The cholera vibrio and the organism were planted out at 

 the same time on an agar-slope, and incubated at room or blood- 

 temperature. 



(3) The vibrio and the organism .were planted out in slightly 

 alkaline broth and incubated as above. 



(4) The organism was inoculated into a recent broth culture 

 of the cholera vibrio. 



(5) Cholera vibrios were planted out in a recent broth culture 

 of the organism. 



(6) Ten hours after the inoculation made under (2), (3), (4), 

 and (5), and subsequently from time to time, a loopful of the 

 culture was removed and plated out in gelatine. 



(7) Care was also taken to plant out the above mixed cultures 

 on fresh media, and at different temperatures, in order to make 

 sure that the culture which had disappeared was not able to 

 develop under more favourable circumstances. 



Kitasato obtained the following results : 



PATHOGENIC ORGANISMS. 



Cholera Vibrios and- Anthrax Bacilli. The cholera vibrios 

 were not in any way injured by admixture with anthrax bacilli ; 

 on the other hand, the anthrax bacilli were quite destroyed at 

 the end of two weeks. 



Cholera Vibrios and Typhoid Bacilli. The typhoid bacilli 

 were not in any way inj ured by the vibrios. At first the former 

 were slightly overgrown by the latter, but after a few days both 

 microbes grew well and were found alive at the end of three 

 months. 



Cholera Vibrios and Friedlander's Pneumo-bacilU. The 

 pneumo-bacilli disappeared at the end of a month, whilst the 

 cholera vibrios were still alive at the end of three months. 



