236 



Profs. Percy Frankland and Marshall Ward. 



Turning in the first instance to Table XII, in which the results for the 

 unsterilised water are recorded, it will be seen from the plates poured 

 on the day of infection (July 8, 1892) that the sporiferous anthrax 

 bacilli had been introduced to tbe amount of about 5000 per cubic 

 centimetre, the water bacteria being present to the number of about 

 600 per cubic centimetre only. From Tables XIII and XIY it will be 

 seen that the sporiferous anthrax bacilli had been introduced into 

 the sterile waters in also just the same numbers as into the unsterile 

 water, viz., about 5000 per cubic centimetre. 



In the case of the unsterilised water, there was no difficulty in 

 counting the anthrax colonies on the plates poured on the day of 

 infection (July 8, 1892) ; but already, four days afterwards, the 

 number of water bacteria had so greatly increased that the plates 

 could not be preserved long enough for the proper development of 

 the anthrax colonies, although they could still be just recognised as 

 minute dots with a low power of the microscope. The multiplication 

 of the water bacteria was greatest in the flask which had been kept at 

 18 — 20° C, although it was also very considerable in the one which 

 had been in the refrigerator at about 9° C. 



A fortnight (July 22, 1892) after the day of infection, anthrax 

 was easily discoverable in large numbers by means of the special 

 method of preliminary heating to destroy the water bacteria, there 

 being three or four times as many colonies on the plates from the 

 refrigerator flask as on those from the flask which had been kept at 

 18 — 20° C. This difference becomes still further accentuated later 

 on, for on examining those flasks which had been continuously at the 

 temperature (19° C.) of the incubator up to October 18, 1892, it was 

 found that no anthrax could be demonstrated, whilst in those flasks 

 which had been at the temperature of the refrigerator (9° C.) up 

 to July 23, 1892, and up to 15° C. afterwards, a large number of 

 anthrax colonies was obtained on cultivation.. This contrast was pre- 

 sented both by those flasks which were kept continuously in the dark, 

 as well as by those which had been placed in the daylight from 

 July 23, 1892, onwards. From this it would appear that the spores 

 of anthrax undergo markedly more rapid degeneration in the un- 

 sterilised Loch Katrine water at 20° C. than at 9° C. As will be 

 seen presently, this striking phenomenon is not exhibited by the 

 sterilised Loch Katrine water, in which there is little difference 

 between the numbers of anthrax colonies obtained from the incubator 

 and refrigerator flasks respectively. 



It became, of course, particularly interesting to ascertain whether 

 these remarkable differences between the incubator and refrigerator 

 flasks would be maintained also in respect of virulence, and to deter- 

 mine this point thj following direct experiments were made : — 



Animal Experiment No. 11. — On October ] 6, 1892, 1 c.c. of the 



