Report on the Bacteriology of Water. 



381 



3CO 

 900 

 200 

 60 

 240 

 20 

 COO 

 100 

 160 

 140 

 120 

 100 

 00 

 60 

 40 



12345676910 II 121 2345 



The curves show that the doubling periods ran approximately 

 thus : 



7 '715 -4 = 6 P.M. to 9.10 P.M. = 190 min. at 12 '51312 '75 for the red, 

 whereas the blue did not double (2 -7 5 '4 = 6 P.M. to 10 -30 = 270 min. at same 

 temperature) till 80 mius. later. 



On November 17 spores which had been sown overnight in normal 

 10 per cent, gelatine at 13 C. had germinated to filaments 200 to 

 300 ft long by 10 A.M. ; two cultures were examined and exposed at 

 10.15 A.M., at the south of the laboratory, care being taken that the 

 sun was behind a building, and could not touch the cultures. 



One culture was under blue and the other under red glass, each with 

 its control thermometer cell, and side by side on a mirror, all open to 

 the blue sky. The day was cold, and growth very slow. Matchbox 

 screens were used. 



The temperature ran as follows : 



Blue. Ked. 



Time. C. 0. 



10.15 A.M. 12-5 . 12-25 



10.35 11-75 11-0 



12.15 P.M. 12-25 11-75 



1.0 12-25 11-75 



3.15 10-2 10-0 



