200 



Profs. Percy Frankland and Marshall Ward. 



That the anthrax had undergone considerable attenuation through 

 its long residence in this unsterile water appears from its tardy 

 causation of death with the non-typical symptom of but slight 

 enlargement of the spleen. 



4. Bacteriological Examination of the Infected Thames Water Sterilised 

 by Filtration through Porous Porcelain and by Steam respectively 

 (First Series). 



The results recorded in Tables IY and Y may be conveniently con- 

 sidered together. These tables exhibit the effect of introducing a 

 small number of spore-bearing anthrax bacilli into Thames water pre- 

 viously sterilised, on the one hand by filtration through porous 

 porcelain, and on the other by steam. 



In these waters the recognition and numeration of the anthrax 

 colonies in the plate cultivations is, of course, attended with no diffi- 

 culty, and, indeed, it is only by means of these that an estimate of the 

 number of anthrax organisms introduced into the unsterilised water 

 can be formed. It will be seen that the number of anthrax germs 

 introduced into each cubic centimetre of the waters of this Series I 

 amounted to from 30 to 100. The fate of these in the unsterilised 

 water we have already traced ; in these sterilised waters it will be 

 seen that they undergo little or no change in numbers during a period 

 of upwards of 3 months, nor is there any material difference in their 

 deportment in the waters sterilised in the two different ways. 



Although these waters, which had been submitted to steam and 

 filtration through porcelain respectively, were sterile in the first 

 instance, it was only to be expected that in repeatedly opening the 

 flasks for the purpose of preparing the plate cultivations, some would 

 become contaminated with air-carried bacteria, &c, the presence 

 of such intruding forms in a few of the flasks will be found recorded 

 in the tables, but they generally gave rise to no difficulty in con- 

 nexion with the plate cultivations. 



It will be seen that in the case of these sterilised waters there is 

 evidence of a very slight increase in the number of anthrax colonies 

 after the first day, the number subsequently falling to about the 

 original. 



At the foot of Table IY will be seen the result of applying the 

 special method of anthrax identification, which had to be relied on 

 exclusively in the case of the unsterilised waters. On comparing the 

 number of anthrax colonies found by this method with that obtained 

 by ordinary plate cultivation, it will be seen that the greater portion 

 of the anthrax organisms are either actually destroyed in the process 

 of heating to 70° C, for 2 minutes, or, at any rate, are so far enfeebled 

 that they do not subsequently develop in the gelatine. Thus, whilst 



