1206 ON THE EXAMINATION OF WATER FROM THE SYDNEY SUPPLY. 



The above figures indicate a relative purity of the water, if 

 compared with those obtained on previous occasions. The greatest 

 number of bacterial colonies which made their appearance on the 

 plates of nutritive gelatine was, as is seen, 540, whereas in 

 three cases with 8, 18, 44 colonies respectively, the water might 

 be looked upon as nearly free from micro-organisms. 



As far as the kinds of bacteria which came under observation 

 are concerned, several new forms were isolated in addition to some 

 of those described before. These bacteria, or at least the more 

 interesting of them, will be dealt with at another time. 



Here it may suffice to mention that, so far, pathogenic species 

 have not been found to occur in the tap-water under consideration. 



With regard to the sample of water derived from the Prospect 

 Reservoir, alluded to above, I have to state that it was not handed 

 over to me until some time had elapsed from the moment it 

 had been taken. On examination it proved to be exceedingly rich 

 in bacteria capable of propagation in nutrient gelatine ; for about 

 4,000 colonies could be referred to 1 ccm. of the water under 

 treatment. Liquefying colonieswere comparatively very few. 



