BACTERIA IN WATER 59 



B. TYPHOSUS B. COLI 



Broth containing Q.T) per cent. Phenol Grows well. 

 or Formalin (i : 7000): No growth. 



Thermal Death Point : 62 C. for five 66 C. for five minutes (Klein), 

 minutes (Klein). 



Vitality in Water and Sewage : The B. coli retains for a much longer 

 Typhoid bacillus soon ceases to time its vitality and power of self- 



multiply and readily dies (Klein). multiplication (Klein). 



The two species, Bacillus typhosus and B. coli, agree in 

 possessing the following characters : no spores, no liquefac- 

 tion of gelatine ; both grow well on phenolated gelatine, and 

 in Parietti's broth ; both act similarly upon animals, though 

 typhoid fever is not a specific disease of animals. 



The Bacillus typhosus, though a somewhat susceptible 

 bacillus, can when dried retain its vitality for weeks. In 

 sewage it is very difficult indeed to detect, and is soon 

 crowded out. Dr. Andrews and Mr. Parry Laws, in their 

 bacterial researches into sewage for the London County 

 Council, 1 found that when they examined specially infected 

 typhoid sewage it was only with extreme difficulty they 

 isolated Eberth's bacillus. In ordinary sewage it is clear 

 such difficulty would be greatly enhanced. 



We have pointed out elsewhere the relation between soil 

 and typhoid. In water, even though we know it is a vehicle 

 of the disease, the Bacillus typhosus has been only very rarely 

 detected. The difficulties in separating the bacillus from 

 waters (like that at Maidstone, for example), which appear 

 definitely to have been the vehicle of the disease, are mani- 

 fold. To begin with, the enormous dilution must be borne 

 in mind, a comparatively small amount of contamination 

 being introduced into large quantities of water. Secondly, 

 the huge group of the B. coli species considerably compli- 

 cates the issues, for it copiously accompanies the typhoid, 

 and is always able to outgrow it. Further, we must bear in 



Report on the Micro-organisms of Sewage, Reports to L. C. C., 1894, 

 No. 216. 



