330 ON THE EXAMINATION OF WATER PROM THE SYDNEY SUPPLY. 



The mean number of colonies out of these figures, for 1 ccm. of 

 water, is 176, among which there are 23 or 24 colonies = to about 

 13^ p.c, which caused liquefaction of the nutrient gelatine. 



Save a few interruptions these bacteriological examinations of 

 Sydney Tap- Water extend now over nearly oae year (see these 

 Proceedings, September 1886, December 1886, March 1887), and 

 taking into consideration the average numbers of bacterial colonies 

 obtained each of the four times, we arrive at a mean of 246 for one 

 cubiccentim., out of which 67, or about 27J p.c, were such as 

 liquefied the gelatine. At the beginning it was my intention to 

 describe all kinds of bacteria met with ; but by-and-by the number of 

 these became so large that from want of time and opportunity I 

 had to give the idea up. In order to have a practical bearing, the 

 investigation of every kind of bacterium found in potable waters 

 has to deal with its principal biological properties, and, as already 

 mentioned previously, it has to be ascertained which of the forms 

 cultivated are so-called "water-bacteria," and which ones must 

 be looked upon as merely accidental. But without having been 

 able to do this I trust that the results of my examinations, in the 

 form offered, will not be quite devoid of interest. The bacillus 

 of typhoid fever I have not yet come across in Sydney water, 

 although now and then bacteria came under notice which were not 

 unlike it in several points. By that I do not mean to say that 

 the true microbe of typhoid fever might not occasionally be 

 present in this water ; it mxast be borne in mind that, after all, 

 the chances to obtain it from this source will be bat slight in face 

 of the fact that comparatively only minute portions of it, up to 

 1 ccm., can be taken for each individual test. However, when 

 there is a strong suspicion of its being grossly contaminated with 

 the germs of typhoid fever, the chances to actually demonsti'ate 

 these out of the water, naturally increase, and on such occasions 

 the carrying out of bacteriological examinations will prove to be 

 of special value. 



