Report on the Bacteriology of Water. 



219 



anthrax was found in both of them, are recorded at the foot of 

 Table VIII. Thus: 



Animal Experiment No. 18. — On October 21, 1892, 1 c.c. of the 

 water in flask " 3 1, unfiltered Thames water, infected with anthrax, 

 March 25, 1892," was subcutaneously injected into a white mouse. 

 The mouse died within 3 days 17 hours; the spleen was much 

 enlarged, and although no anthrax bacilli could be found either in 

 the latter or in the kidney with the microscope, gelatine cultivations 

 prepared from the spleen developed the characteristic growths in due 

 course, leaving no doubt that the animal had succumbed to anthrax. 



Animal Experiment No. 27. — On October 31, 1892, 1 c.c. of water 

 from the flask "IE, unfiltered Thames water (Second Series), in- 

 fected with anthrax, March 25, 1892," was subcutaneously injected 

 into a white mouse. The mouse died within 2 days 18 J hours, 

 anthrax bacilli being found in the spleen, and the characteristic 

 growth obtained on gelatine cultivation. 



These experiments with the unfiltered Thames water (Second 

 Series) on being contrasted with those of the same water (First 

 Series) show that the virulence was distinctly greater in the Second 

 than in the First Series, for both incubator and refrigerator flasks of 

 the Second Series, irrespectively of whether they had been kept in 

 darkness or in the daylight, were sufficiently virulent to be fatal to 

 mice. That the anthrax must have suffered a certain amount of at- 

 tenuation is clear from the fact that one of the mice (Experiment 

 No. 26) remained alive after receiving 1 c.c. of the water in flask 

 " 2 1," although a second mouse similarly inoculated succumbed. 

 This unquestionably greater virulence of the unfiltered Thames water 

 {Second Series) is, doubtless, due to the much larger number of anthrax 

 germs with which the water was infected in the Second than in the First 

 Series. It is particularly interesting that the mouse in Experiment 

 No. 26 remained alive, because from the plate cultivations (see 

 Table V III) it is perfectly certain that in the 1 c.c. injected a number 

 of living anthrax germs must have been present, and it is obvious, 

 therefore, that their virulence must have been weakened by the long 

 residence in the unsterilised water. 



2. Experiments with Sterilised Thames Water (Second Series). 



The results of the experiments made on Thames water sterilised 

 by filtration through porous porcelain are recorded in Table IX, 

 whilst those on the same water sterilised by steam are given in 

 Table X. From these tables it will be seen that about 6000 anthrax 

 organisms per cubic centimetre were introduced into the porcelain- 

 filtered water, and about 8000 into the steamed water; whilst in 

 Table VIII it was shown that about 12,000 were introduced into the 



