Report on the Bacteriology of Water. 



193 



water at this time contained upwards of 100,000 water bacteria in 

 1 c.c, yet after beating as above for five minutes to 50° C, only 

 from 35 to 39 colonies per cubic centimetre made their appear- 

 ance, and amongst these several were easily recognisable as those 

 of anthrax. Again, on the same day, other portions of the 

 same water were heated to 70° 0. for two minutes, after which 

 only from 10 to 30 colonies per cubic centimetre made their 

 appearance, amongst which from 4 to 10 were recognisable as 

 anthrax. Other portions of the same water were heated on the same 

 day to 90° C. for two minutes, with the result that only from 7 to 10 

 colonies per cubic centimetre appeared, of which from 3 to 6 were 

 found to be anthrax. 



Thus by this simple method comparatively large volumes (up to 

 3 c.c. have been used, but there is no reason why even larger quan- 

 tities should not, if necessary, be employed) of water swarming with 

 water bacteria can be operated on and sifted, so to speak, for anthrax. 



From Table II it will be seen that this method was repeatedly 

 employed on the anthrax-inf ected unfiltered Thames water in question, 

 in most cases the temperature of 70° 0. for two minutes being re- 

 sorted to. 



Employing this method it will be seen from the table that it 

 became more and more difficult to discover anthrax in the water, although 

 even after nearly four months anthrax could still be just traced bo/h in the 

 water, which had remained at summer (18 — 20° C.) temperature in the 

 incubator, as well as in that preserved at the winter temperature 

 (6 — 10° C.) of the refrigerator. 



It now became of interest to ascertain whether the water in which 

 anthrax could just be barely traced by cultivation contained that 

 anthrax in a virulent state. In consequence of the delay which 

 occurred in my obtaining the necessary licence to perform these 

 experiments, I was not able to attack this problem until October 7, 

 1892, or nearly seven months after the water was infected with anthrax. 



Animal Experiment No. 1. — On October 7, 1892, 1 c.c. of water 

 from " Flask 3 1, unfiltered Thames water infected with anthrax, 

 March 18, 1892," was subcutaneously injected into a white mouse. 

 The mouse did not succumb to anthrax, but is still living, 32 days 

 after the operation. 



Animal Experiment No. 2. — On the same day, October 7, 1892, 

 1 c.c. of water from " Flask 3 R, unfiltered Thames water, infected 

 with anthrax, March 18, 1892," was subcutaneously injected into a 

 white mouse. This mouse lived for 18 days 20J hours after the 

 operation, and, of course, did not succumb to anthrax ; no bacilli could 

 be found in the spleen, nor by cultivation in gelatine. 



From these experiments it is obvious that on October 7, 1892, or 

 nearly seven months after infecting this unfiltered Thames water 



