216* BACTERIOLOGICAL EXAMINATION OF WATER 



first, and in two weeks was the only organism that could be 

 found ; but later the typhoid bacillus, present apparently in too 

 few numbers to be seen 011 the plate when growing at the shed 

 temperature, gradually increased, and in the final experiment 

 at 37 C. assumed the upper hand. The experiments made 

 with Chichester 3 were ot special interest. Chichester 3 was a 

 stout bacillus with rounded ends, forming long chains. On 

 potato it formed an abundant yellow growth, but it did not pro- 

 duce indol nor form gas in sugar media. It liquefied gelatine 

 slowly, and formed dense opaque colonies on agar plates. No 

 confusion could arise between this organism and the typhoid 

 bacillus. The experiments showed that Chichester 3 had 

 difficulty in growing in the presence of the typhoid bacillus. 

 It grew readily enough in a mixture of water and broth when 

 it was the only organism present ; but when the typhoid 

 bacillus was also present Chichester 3 could not establish itself, 

 it did not grow or was killed out altogether. This took place 

 at low temperature and at 37 C. When, however, Chichester 

 3 was grown in the sterilised soil from which it was obtained, 

 its chances of growth and multiplication were greatly increased, 

 and in one case it so far gained the mastery that no typhoid 

 bacilli could be found after fifteen days. 



The latest contribution to the study of the B. typhosus in 

 relation to other micro-organisms is furnished by the researches 

 of Remy on the antagonism of the B. coli and the B. typhosus. 

 This observer believes that the failure to isolate the B. typhosus 

 when growing side by side with other bacteria is not due to the 

 disappearance of the typhoid organism but to the imperfection 

 of the methods employed to isolate it. He added to a 

 flask containing a litre of peptonised water (peptone 3 per 

 cent., sodium chloride 0'5 per cent.), exactly neutralised, 5 c.c. 

 of a twenty-four hours culture of B. typhosus and 5 c.c. of a 

 twenty-four hours culture of B. coli. The same procedure 

 was followed with a flask containing peptonised water to which, 

 after neutralisation, 0'5 per 1000 of H 2 SO 4 was added. The 

 flasks were kept at the room temperature, and examined at 

 intervals by plating out the contents in Remy's special medium. 

 After five days association the B. typhosus was found not to 

 be agglutinated by anti-typhoid serum, diluted 1-10, though 



