BY DR. 0. KATZ. 265 



SO far as liquefying colonies were proportionately far more 

 numei'ous, thus resembling, as it were, cultures made from the 

 ordinary Sydney tap- water. 



From the results thus obtained, it may be inferred that the 

 quality of the Sydney ice could not always be pronounced to come 

 up to what a good drinking-water is required to be fi'om the stand- 

 point of public sanitation. While, on the one hand, it was 

 gratifying to learn that not few samples (notably with reference 

 to the ice from the works of the N.S.W. Fresh Food and Ice 

 Company), proved themselves absolutely free or tolerably free from 

 living bacterial elements, on the other hand, some objection must 

 be taken to a series of other samples, since they were inhabited by 

 rather too large numbers of living microbes to be passed as fit for 

 being used as additions to articles of food, or in the treatment of 

 wounds. But it would be unjustifiable to say that a sample of water 

 or ice must be looked upon as objectionable, solely for the reason 

 of its containing large quantities of germs ; as has already been 

 pointed out by other observers, the danger is that if such is the case, 

 pathogenic species might possibly also be present among them. 

 However, a rough examination of the colonies obtained in the 

 gelatine-tubes from the Sydney ice showed that there were, so far 

 as known, no infectious organisms. As already alluded to, the 

 colonies were not always exclusively such as we are accustomed to 

 find in the water from the Sydney supply. My impression is, 

 that the water to be transformed to ice received, somehow or 

 other, at least in a number of instances, secondary microbian mate- 

 rial from without. Were we to apply to the condition of the 

 Sydney ice in each case the law made out by Prudden (I.e.), and 

 Bordoui-Uffreduzzi (I.e.), namely, that 90p.c. of the water-bacteria 

 become destroyed by the process of freezing, we should arrive at 

 figures which, my examinations of the Sydney Tap Water (these 

 Proceedings, 2nd Series, Vol. I., pp. 907, 1205; Vol. II., 

 pp. 151, 329.), lead me to believe, do not appear to hold true for 

 this water. 



The bacteriological analysis of fifty-six samples of water from 

 the Sydney supply (derived from a tap in the Linuean Society's 



