84 Elements of Water Bacteriology. 



scopically for comma-shaped organisms, and agar plate 

 cultures are made which are likewise incubated at 37 

 degrees. If any colonies showing the characteristic* 

 appearance of the cholera bacillus are found, these are 

 examined microscopically, and if comma-shaped organ- 

 isms are present, inoculations are made into fresh tubes 

 to be further tested by means of the indol reaction and by 

 inoculation into animals. The existence of other spirilla 

 of some pathogenic power renders necessary the greatest 

 care and caution in claiming positive isolations. That 

 no great improvement on Koch's method has been made 

 during the last ten years seems apparent from the state- 

 ments of Kolle and Gotschlich (Kolle and Gotschlich, 

 1903), who employed " the peptone method with subse- 

 quent agar cultivation " in the isolation of the organisms 

 from feces of cholera patients during the epidemic in 

 Egypt in 1902. 



Other pathogenic organisms have been isolated from 

 waters, according to the accounts of numerous investi- 

 gators, but from the sanitary point of view the typhoid 

 and cholera bacilli are of most importance since these are 

 manifestly the germs of disease most likely to be dissemi- 

 nated through this medium. For the detection of B. 

 anthracis and other spore-forming pathogenic bacteria 

 which may at times gain access to water from stockyards, 

 slaughter-houses, etc., the method suggested by Frankland 

 (Frankland, 1894) may be adopted. The water to be 

 examined is heated to 90 degrees for two minutes and then 



