M. Whbldalb 



153 



cultures. I therefore made a number of sugar-feeding experiments 

 with various species and at the same time I examined the starch 

 contents of the leaves after this treatment. 



The leaves employed were first kept in the dark until starch-free, 

 and a piece of each leaf was placed, after this treatment, in methylated 

 spirit as a control. Portions of the same leaf were then floated, upper 

 surface downwards, in two dishes, one containing 3 7o cane-sugar solu- 

 tion, the other distilled water. Both dishes were placed under a bell-jar 

 together with a dish containing strong caustic potash solution, air being 

 allowed to enter the bell-jar only by means of a tube containing soda- 

 lime. Control dishes of sugar solution and distilled water containing 

 further portions of the same leaf were placed under a bell-jar without 

 potash solution. After an interval of from 7-10 days, any development 

 of pigment was noted, and the leaf portions were then placed in methy- 

 lated spirit until colourless and sections, after treatment with strong 

 chloral hydrate solution and iodine, were examined for starch contents. 



The results are tabulated as follows : — 



