1 86 The Story of the Bacteria 



true for diphtheria or the wound diseases, 

 and doubtless many others, but the spread of 

 these latter diseases in this way is no doubt 

 quite infrequent. 



It is typhoid fever, whose germs, of all 

 those which cause disease, are, so far as we 

 now know, most apt to be spread by pol- 

 luted water. The discharges from persons ill 

 of typhoid fever, thrown without disinfection 

 into the vaults of country or village out-houses 

 which, in an appalling number of cases, are 

 in direct communication, through under- 

 ground channels, with the wells, or with 

 springs from which the farmer supplies the 

 family or guests, may pass, with but a very 

 moderate dilution into the digestive tracts of 

 the unsuspecting victim. It is ignorance, and 

 carelessness, not Fate which, under these 

 conditions, sets up an epidemic of typhoid 

 fever. 



The water supplies of large towns come, for 

 the most part, either from large rivers, or 

 lakes, or artificial reservoirs along the course 

 of smaller streams, or from artificial wells, 

 which, piercing the upper strata, gain access 



