Report on the Bacteriology of Water. 397 



due to the increasing stiffness of the gelatine at the low temperatures, 

 and to the difficulty the feeble growth had in peptonising so weak 

 and stiff a medium, and partly to the lack of oxygen consequent on 

 congelation. 



On July 17 spores were sown as before, and at once put at 23 in 

 the Sachs' box: this was 8.30 A.M. The temperatures during the 

 morning, &c., ran as follows : 



Temp. 

 Time. 0. 



8.30A.M. = 23-0 



9.10 = 23-75 



9.30 = 23-25 



10.5 = 23-2 



11.50 = 23-25 



12.20P.M. = 23-25 



12.40 = 23-5 



1.30 = 24-0 



1 40 " = 22-75 } ( wing t0 my P enin S the ^ 



1.55 ", - 23-0 



2.10 = 24-0 



3.15 = 24-0 



3.16 = 23-0 (opened box) 

 4.20 = 23-5 



5.5 = 23-0 



5.12 = 22'0 (opened side door) 



I now began the measurements, and continued them till 8.15 P.M. 

 In all these cases where only the doubling periods are given, it must 

 be understood that the table of growths was prepared in detail, and 

 the curve plotted. The tables and curves are too numerous to give 

 in full. 



The doubling periods were as follows : 



1. 31 -5 63 n in 56 minutes at 23 -122 '7 C. 



2. 63 -0126 53 22 -724 -25 C. 



Normal doubling period : 



50-5101 /* = 6 P.M. 6.51 P.M. = 51 minutes at 23 227 23'1 C. 



On July 11 I arranged for a culture at 25 C., approximately 

 constant temperature, in Sachs' chamber. Spores were sown at 9.30 

 in weak gelatine,* and at once put in, though the chamber was uot 



* Weak gelatine here and throughout = a stiff gelatine (10 per cent.) with only 

 0'5 per cent, of broth. 



