Study of Spirogyra nitida. 



249 



A few examples, taken at random from the series of ex- 

 periments, indicate the time in minutes. Each experiment 

 conducted in colored light was checked by a similar test in 

 white light, the time required in both cases being here 

 given : 



Darknkss. 



Exp. i. 



White, 10 minutes. 

 Darkness, 13 " 



l'.XP. I. 



White, 9 minutes. 

 Violet, 18 " 



Exp. 1. 

 White, 11 minutes. 

 Blue, 15 



Exp. 1. 

 White, 14 minutes. 

 Green, 15 



Exp. 1. 

 White, 12 minutes. 

 Yellow, 9 



Exp. 1. 

 White, 15 minutes. 

 Orange, 13 " 



Exp. 1. 

 White, 9 minutes. 

 Red, 9 



gXP. 2. 



White, 10 minutes. 

 Darkness, 12.75 minutes. 



Violet. 



Blue. 



Exp. 2. 

 White, 22 minutes. 

 Violet, 45 " 



Exp. 2. 

 White, 9 minutes. 

 Blue, 12 " 



Green. 



Yellow. 



Orange. 



Red. 



Exp. 2. 

 White, 10 minutes. 

 Green, 12 " 



Exp. 2. 

 White, 13 minutes. 

 Yellow, 9.5 " 



Exp. 2. 

 White, 15 minutes. 

 Orange, 13 " 



Exp 2. 

 White, 11 minutes. 

 Red, 11 



The light rays, from the above data, attain their maxi- 

 mum for diastase in the yellow, and in darkness the action 

 is slower than in light. Under orange the change from 

 starch into sugar is slightly slower than with yellow, while 

 red light requires the same length of time as white. Pro- 

 gressing toward the more refrangible end of the spectrum 

 we find the green band a little slower than white light, and 



