98 ELEMENTS OF WATER BACTERIOLOGY 



blue. The medium is best used after the Koch enrich- 

 ment method described above. 



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 

 disseminated 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 

 2 minutes and then plated, the characteristic colonies 

 of the anthrax organism being much more easily dis- 

 cerned after the destruction of tne numerous non- 

 sporing water bacteria. 



