Report on the Bacteriology of Water. 417 



Normal doubling periods : 



1428 /* - 11.15 A.M. 11.53 A.M. = 38 minutes at 24 '5 C. 

 2856 - 11.53 12.39 P.M. =46 24 -524 '8 C. 



The rapid germination indicates the neighbourhood of optimum 

 temperature. 



This filament was now lost, and another taken as follows : 



Doubling period : 



1. 67 -5135 p = 2 P.M. 2.50 P.M. = 50 minutes at 24 '5 24 '75 24 '6 C. 



Or, calculating back : 



238 119 At = 2.41 P.M. 3.25 P.M. = 44 minutes at 24 -75 24 -5 C. 



On July 28 spores in broth + 1 per cent, gelatine were sown and 

 put into Sach's box at 23'5 C. at 8 A.M. The temperature was slowly 

 raised to 26 C. as follows : 



Temp. 



Time. C. 



8.00 A.M. = 23-5 



9.00 = 24-0 



9.30 = 24-5 

 10.10 = 25-75 

 10.45 = 26-00 

 11.00 = 25-75 

 11.15 = 25-9 

 11.35 = 26-0 



12.30 P.M. = 26'0 (germination begun) 

 12.45 = 26-0 



But fell to 24'75 on opening to arrange. 



I now found a rodlet 5 divisions long (= 5 x 4'5) = 22'5 /i, and 

 began measuring. 

 Doubling periods : 



1. 22 -545 n = 12.45 P.M. 1.26 P.M. = 41 minutes at 25 -026 "0 C. 



2. 45 -090 * - 1.26 2.10 = 44 26 '026 '5 C. 



This filament had another spore attached to it, and germinating 

 there ^ possibly disturbances resulted, so I found another filament, 

 and measured it as follows : 



Normal doubling period : 



3672 n = 1.10 P.M. 1.58 P.M. = 48 minutes at 25-826-4 C. 



Or, calculated back : 



74 -2537 AI = 48 minutes at 25 '826 '4 C. 



* Calculated from curve. 



