Report on the Bacteriology of Water. 



295 



in the dark throughout the whole period of the experiment, except 

 at the short intervals (one to two minutes each) necessary for 

 recording the growth. 



The temperature at 1011 A.M. was 16 C., but it rose to 2021 C. 

 at 2 P.M., and remained at that until about 7 P.M., when it fell until it 

 was again 16 C. at 8.30 P.M., and stayed so through the night. 



The spore germinated vigorously, and the germinal rodlet was 

 10 ft long by 2 P.M. The following table shows its further behaviour : 



On scrutinising this table and drawing the curve representing the 

 increments, it is evident that we have the effects of the higher tem- 

 perature expressing themselves in conjunction with those (if there 

 are any) due to absence of light. 



The characters of the culture itself were all those of a superbly 

 vigorous organism, and the crop of spores developed at the end of 

 its growth the spores were ripe in 72 hours from sowing was a 

 remarkably fine one. 



As we see, in the period of growth recorded from 2 P.M. to 

 9.27 P.M., the rodlet elongated from 10 to 240 //. In other words, 

 it grew 230 /*, which is 115 times the length of the spore, in 

 7-^ hours. This would give an average growth of about 0*5 /t per 

 minute throughout the period referred to. 



On comparing these results with what were obtained during 

 growth at the same temperature in ordinary daylight, I could not see 

 how to escape the conclusion that the rapid rise of the curve is 

 chiefly due to the absence of the inhibitory effect of the light.* 



* Unless a question which arose later the temperature inside the culture- 

 chamber is very different from that recorded by the thermometer standing, as here, 

 outside the system. 



