THE STORY OF THE BACTERIA. 89 



finally, sooner or later, gain access to the food 

 or drink of the inmates. This mode of con- 

 veyance of the germ of typhoid fever has not 

 yet been proven, but, as a reasonable hypothe- 

 sis, is closely in accord with what we know but 

 too well of the outbreaks of typhoid fever 

 which so often occur on the return of house- 

 holds in the autumn to their city homes. 



It has been abundantly proven by careful 

 experiments that the typhoid bacillus can re- 

 main alive for long periods when frozen solidly 

 in a block of ice. The disease-producing bac- 

 teria which may be conveyed in ice in impure 

 water to the body will be considered in a sub- 

 sequent chapter. 



