Report on the Bacteriology of Water. 



239 



In order to test the virulence of the porcelain-filtered water, I 

 made the following experiments : — 



Animal Experiment No. 15. — On October 17, 1892, 1 c.c. of water 

 from the flask " 3 1, Loch Katrine, porcelain-filtered, infected with 

 anthrax, July 8, 1892, exposed to daylight since July 23, 1892," was 

 subcutaneously injected into a white mouse. The mouse died within 

 2 days 1-7 hours ; the body exhibited much oedema ; the spleen was 

 slightly enlarged, and anthrax bacilli were found in it, both by the 

 microscope and by gelatine cultivation. 



The porcelain-filtered Loch Katrine water was, the?*efore, fully virulent 

 more than three months after infection with anthrax. 



Again, if we turn to Table XIV, in which the results with the 

 steam-sterilised Loch Katrine water are recorded, we find that the 

 multiplication after four days is more pronounced than in Table XIII, 

 and, again, it will be seen that the multiplication is markedly greater 

 in the flask kept at 18 — 20° C. than in the one kept in the refriger- 

 ator, although the latter also shows a multiplication of 100 per cent. 

 In the later examinations, after the temperature of the refrigerator 

 had been allowed to rise to that of the room (about 15° C), the 

 numbers in the incubator and refrigerator flasks became more 

 equalised ; on the whole, the numbers were, at the final examination, 

 greater in the refrigerator than in the incubator flasks, and this is 

 markedly the case also in those flasks which, from July 23, 1892, 

 onwards, were exposed to diffused daylight. 



To test the virulence of the steam-sterilised Loch Katrine water, 

 the following experiment was made : — 



Animal Experiment No. 14. — 1 c.c. of water from the flask " 3 I, 

 Loch Katrine, steam-sterilised, infected with anthrax, July 8, 1892, 

 exposed to daylight since July 23, 1892," was subcutaneously injected 

 into a mouse. The mouse died within 1 day 20 hours ; the body 

 exhibited extensive oedema ; the spleen was very much enlarged, and 

 was found to be full of anthrax bacilli, which yielded the charac- 

 teristic growth in gelatine cultivation. 



Thus, the steam-sterilised Loch Katrine water ivas highly virulent 

 more than three months after heing infected with anthrax. 



Conclusions to Part I. 



The results obtained by me in the course of the above investigation 

 on the vitality and virulence of anthrax spores in potable water may 

 be summarised in the following statements : — 



1. Three distinct series of experiments were made, viz. : — 



Series I, in which Thames water collected above Staines was used, 

 and a very small number of anthrax germs introduced into the 

 water (pp. 181—213). 



