Report on the Bacteriology of Water. 



457 



At 8.34 the filament had carved badly, and began breaking up, and 

 at 8.49 it was broken into several writhing carved segments, difficult 

 to measure. At 8.51 all growth had ceased, and by 9.5 the broken 

 fragments were becoming granular, the temperature meanwhile 

 having gone up to over 39 C. 



On December 3 spores sown at 9 A.M., normal gelatine, at 22 C., 

 were put into measurement at temperatures near 39 40 C. at 

 9.15 P.M. On opening the Sachs' box the temperature fell from 

 39-75 to 35, and had to work up again with some difficulty, as the 

 opening of the side windows, &c., has more effect at these high tem- 

 peratures than at lower ones. 



The results are as follows : 



Curve 160, p. 442. 



At 10.39 the filament, growing no longer, sharply contracted to 

 117 ft, and passed over into the granular condition which indicates 

 death. 



This case is interesting, because it evidently marks the limit of 

 possible growth of this bacillus as nearly as possible. The specimen 

 was a very vigorous one, and there was no reason why it should not 

 have gOne on growing vigorously for some time yet at temperatures 

 near the optimum, and, indeed, we see it began growing at a pretty 

 good rate HB the temperatnre rose to 39 40 from 9.15 to 9.35, and 

 thence the curve depressed more and more, and the doubling period 

 became prolonged to infinity. 



In the curve G H, I have summarised the results of all averages 

 of my curves of normal doubling periods obtained in this way. The 

 ordinates are minutes, the abscissae degrees centigrade. 



VOL. LV11I. 



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