70 Wilcox — Winter Condition of the Reserve Food 



spring. This has been the accepted view until within very 

 recent times. Gris y 66 and '66a also shared in this view and 

 says ('66, page 443): " Qu'il n'y a que deux grandes mouve- 

 ments des matieres nutritives a l'interieur du tronc des arbres : 

 la genese de ces matieres en ete, et leur resorption au printemps." 

 Famintzin and Borodin, '67, noted in their study of a birch 

 (the species is not given) that there was a rapid formation of 

 starch in the spring in the cells of the male catkin and in the 

 young twigs in both of which there had been no starch during 

 the winter. They suggest that this starch might have been 

 formed from the oil that was stored in abundance in the same 

 regions and that gradually disappeared during the period of 

 starch formation. 



Schroeder, '69, in his paper on Acer platinoides came to 

 much the same conclusion, so far as concerns starch, as did 

 Gris. Grebnitzky, '84, studied eighteen species of trees for a 

 period of two years but came to quite different conclusions 

 than either of the others mentioned above. He says (1. c, page 

 157) : " Die Starke wird im Herbst audgespeichert, bleibt 

 jedoch wahrend des Winters nicht als solches erhalten, indem 

 sie wahrscheinlich in Fett iibergeht, in Friihlinge erscheint sie 

 vor dem Knospenbruche wieder." By this we see that Greb- 

 nitzky recognized two periods of starch maximum alternate 

 with two periods of starch minimum in the twigs. He says 

 further that in all the soft-wood trees, as the Linden, all the 

 starch disappears in winter while in the hardwood trees that 

 the starch in the bark only is replaced. 



Baranetzky, '84, held that this change of starch into oil is a 

 process that takes place only in the presence of active proto- 

 plasm and that it goes on faster at higher temperatures than at 

 lower temperatures. And this last assumption seemed to him 

 to explain the fact that the transformation of starch into oil 

 does not take place in roots at all or at least not to such an 

 extent as in stems and all parts above ground. This seems to 

 me to be a mere assumption that does not adequately explain 

 the conditions he considers to exist. Russow, '84, carried on 

 some experimental work in several species of trees. He records 

 a gradual reduction in the amount of starch in the bark and 

 considers that it was replaced by oil. He thought that the 

 amount of starch in the woody part of the stems remained the 

 same during the winter. He further says that the starch reap- 

 peared in the bark in the course of a week in the spring. 



Fischer, '88 and '90, comes to the conclusion that there exists 

 an autumn and a spring maximum period as to the amount of 

 starch in the twigs. He divides the species that he examined 

 into two classes distinguished by the starch in one case chang- 

 ing into oil and in the other into glucose. For further details 



