Report on the Bacteriology of Water. 



197 



80,000 were found in the incubated, and upwards of 100,000 in the 

 refrigerated, water. After 46 days (May 3, 1892) they numbered 

 about 13 ; 000 in the incubated water, whilst after 98 days (June 24, 

 1892) the numbers in the incubated water were about 7,000, and from 

 2.000 to 3,000 in the refrigerated. These latter figures are much the 

 same as were obtained in the uninfected waters (see Table I) after 

 uowards of 7 months. 



3. Bacteriological Examination of the Unsterilised Thames Water {First 

 Series), Filtered through Sivedish Paper and Infected with Anthrax. 



The experiments with the Thames water which had been filtered 

 through Swedish paper prior to infection with anthrax, and which are 

 recorded in Table III (pp. 198 and 199), yielded very much the same 

 results as those made with the unfiltered Thames water recorded in 

 Table II. We find a similar multiplication followed by diminution 

 in the number of water bacteria, both in the flasks kept at summer 

 and winter temperatures respectively. In no single instance was 

 anthrax detected by ordinary plate cultivation, but in the refrigerated 

 water it was found by the special method after 98 days (June 24, 

 1892), whilst with the incubated water the same method failed to 

 find anthrax after 53 days (May 10, 1892), and again after 98 days 

 (June 24, 1892), whilst in two final examinations, after 113 days 

 (July 9, 1892), one again gave a negative result, whilst the other 

 yielded a feeble growth, presenting a very doubtful resemblance to 

 anthrax. It may be taken, therefore, that in the water preserved at 

 summer temperature the degeneration of anthrax was markedly more 

 rapid than in that kept at the winter temperature. 



This infected paper-filtered Thames water was also examined for 

 virulence by direct experiment, as follows : — 



Animal Experiment No. 8. — On October 15, 1892, 1 c.c. of water 

 from the flask " 1 B,, paper-filtered Thames water, infected with 

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

 mouse. The mouse died within 4 days 17 hours ; there was very 

 extensive oedema, and the spleen was not much enlarged ; no bacilli 

 were microscopically found in the spleen, but the characteristic growth 

 was obtained on cultivation in gelatine, thus leaving no doubt that 

 the animal had succumbed to anthrax, although in an attenuated form. 



The result of this experiment is interesting in several respects. 

 Thus, firstly, it shows that in this water anthrax was still present, 

 after 7 months, and in sufficient numbers in 1 c.c. to cause the death of the 

 mouse, whilst it will be remembered that in the unfiltered Thames water 

 this was not the case, so that apparently the removal of a certain propor- 

 tion of the water bacteria by paper filtration had been conducive to the 

 preservation of the anthrax. 



VOL. LIII. P 



