Report on the Bacteriology of Water. 



375 



so arranging the mirrors that the solar image was reflected up on 

 to the cultures and thermometers, again using the same cultures, but 

 selecting yet another filament in each of lengths as nearly equal as 

 possible. 



The results were somewhat startling and puzzling, as the follow- 

 ing tables and curves show : 



Water. 



Curve 66, p. 372. 



The growth stopped, and farther examination showed the filament 

 was dead. 



Bichromate. 



Curve 68, p. 372. 



Here we see clearly enough that at high temperatures (32 34 C.) 

 the bright light acted as a powerful stimulus to rapid growth behind the 

 bichromate, which warded off the blue-violet rays, but brought about 

 rapid diminution of growth and death behind the water. 



It seems extremely probable therefore that, provided there is 

 plenty of food-material of a highly nutritious nature present, the 

 high temperature is in itself merely conducive to intense construc- 

 tive metabolism and growth, but if the blue rays gain access at the 

 same time they so interfere with constructive metabolism or so 

 promote destructive metabolism (perhaps by promoting respiration ?) 

 that rapid death ensues. 



