346 



Profs. Percy Frankland and Marshall Ward. 



At 3.30 all the four cultures were brought into the laboratory and 

 placed side by side under a dark cover, and allowed to grow through 

 the night at 21 C., falling to 20'5 at 10.30 P.M., and to 19'5at 1 A.M., 

 where it remained until 9 A.M., when the last observations were made. 



The two 2.30 cultures were brought in at 6 P.M., and remained 

 side by side with the others through the night. 



If we examine these results (Curves 36 41, p. 343), the striking 

 effects of the bichromate come out more clearly than ever. It is an 

 undeniable fact that the spores germinate more o^ickly, produce 

 stronger and more rapidly developing filaments, and sporify more early 

 after exposure to the light coming through the orange screens than 

 when left in the dark or behind any of the other screens for the same 

 period. 



Why is this ? The reply first suggested is, because the bichromate 

 lets so much of the heat rays through that the spores are raised to a 

 higher temperature. But the same acceleration of germination is 

 seen if the bichromate and CuS0 4 screens are not exposed to the 

 sun, but only to light from the blue sky, and when the temperature 

 of the cells behind them hardly differs at any rate not more than 



* Sown at 10.30 A.M. 



t Sown at 2.30 P.M. 



