324 



Profs. Percy Frankland and Marshall Ward. 



I give the results in any case, though they prove little by them- 

 selves : they on]y show that, either (1) the organism does not 

 rapidly* react to any great extent to quick, small, but considerable, 

 variations of the temperature immediately around the culture- 

 chamber, or (2) the inhibiting action of the light is sufficient to just 

 undo or mask that effect. 



The plan was as follows. A culture drop was prepared as usual, 

 and germination allowed to proceed in the dark for several hours. 



At 12 noon, a germinal filament 5 /t long was selected for observa- 

 tion. The temperature of the interior of the darkened bell-jar, as 

 shown by a thermometer hanging with its bulb close to the culture, 

 was 24 C. The reading and measurement being taken, I left the 

 whole system undisturbed till after 2 o'clock, except to take the 

 temperature readings given in the following tabular resume : 



Time. 



12 noon 



12.18 P.M. 



12.40 



1.0 



1.45 , 



Temp. 

 24 C. 

 25 



28 

 28 

 27-5 



At 2.33 the sun had passed off the window (and it was the direct 

 insolation playing on the wrappings which so raised the temperature 

 of the interior of the bell-jar), and the temperature at once fell to 

 25 C., and measurements were at once begun, as shown in the fol- 

 lowing table (see Curve 18). 





* It does react, however, as the curves show j but the result is not very great in 

 short periods. 



