i8 93 . PLANT NUTRITION. 27 



even modern plant physiology, the work tends to emphasise the 

 necessity that those who would further progress in this department 

 of biology must first be chemists. 



Considering the great labour and patience which these researches 

 must have involved, it may, perhaps, seem ungrateful to express regret 

 that the function of chlorophyll meets with no consideration. Not- 

 withstanding the researches of Engelmann, Pringsheim, Timiriazeff, 

 and many others, this part of the subject is little understood, and 

 now that the morphological and physiological identity of the coloured 

 chloroplast and colourless amyloplast is completely established 

 so far as starch-production from already assimilated materials is 

 concerned, the quite separate function of constructing a proto-carbo- 

 hydrate from carbon dioxide and water by the former, due to its 

 possession of chlorophyll, is of especial interest. 



J. Percival. 



