24 Discussion 



half is capable of regenerating a hat. This experiment is very simple : 

 you cut a number of algae, take the non-nucleated halves. Light is 

 needed to provide energy for the regeneration. You put some of the 

 algae immediately in the light, you keep another batch for one week, 

 another for two weeks or three-four weeks in the dark before exposing 

 them to the light. AVhen you put a batch of non-nucleated algae 

 immediately in the light, you may get about 70 per cent hats. If you 

 leave them one or two weeks in the dark, you still get 70 per cent hats ; 

 but if you leave them three weeks in the dark, you get only 25 per cent 

 hats, and after four weeks you have none. There is something which 

 dies off in the dark as well as in the light. The time when the percentage 

 of the hats decreases (i.e. two weeks) is the same when net protein 

 synthesis and incorporation of ^^COg in the proteins also decrease in the 

 light. 



