W. A. Davis, A. J. Daish and G. C. Sawyer 259 



one- half, is held to prove that the saccharose is formed in the leaf 

 directly and migrates as such to the root in the night. He supports this 

 view by observations on two abnormally formed beets in which the 

 length of the neck had become enormously exaggerated ; these abnormal 

 growths contained cane sugar but no reducing sugar. If reducing 

 sugars wandered from the leaf to the root they should have been found 

 in large amount in the abnormally long necks. The objection to the 

 view that the saccharose wanders as such, which is based on the supposed 

 impermeability of the cell protoplasm to cane sugar, is, according to 

 Strohmer, obviated if one assumes with PfefEer that the protoplasm 

 can change its properties periodically under the influence of a regulating 

 mechanism. In a later paper [19111 Strohmer gives data for the second 

 season's development of the sugar beet grown for seed, and shows that 

 the total saccharose content of the root and principal stem is at the 

 ripening period considerably greater than at flowering ; the saccharose, 

 however, during ripening entirely disappears from the leaves and 

 stalks. This is held to confirm the view that the cane sugar is formed 

 in the leaf and leaves it as such. Reducing sugars, however, predominate 

 in the parts of the plant above ground at the flowering period because 

 they have been formed by the inversion of saccharose, so as to be 

 readily available for the building up of the flowers. Thus, for example, 

 in the main stalk the ratio of reducing sugars to saccharose was 

 11-2 : 4-3. But later on, when ripening is near, the reducing sugar 

 disappears almost completely. 



Stephani [1911] also holds that saccharose is formed in the leaf of 

 the beet and is transferred as such to the root for storage ; the pro- 

 portion of the reducing sugars in the root is generally very small 

 (0-05 to 0-10 per cent.), but in some feeding varieties {Fiitterruben) 

 may be as high as 0-5 per cent. 



Parkin [1912] made a careful study of the sugars present in the leaf 

 of the snowdrop (Galanthus nivalis), to which we shall refer more in 

 detail later. He considers that his analyses strongly favour the view 

 that saccharose is the first recognisable sugar to be formed in the leaf 

 and that the hexoses arise from it through inversion. The rapid rise 

 in cane sugar, which occurs in the leaf when it has been exposed to 

 darkness for some days and is then again placed in sunshine, is particu- 

 larly striking ; thus in one experiment the cane sugar rose after 8 hours 

 exposure to sunlight from 5 per cent, to 12-5 per cent., whilst the hexose 

 changed only from 2-7 to 3-6 per cent. In darkness, on the other hand, 

 it is the saccharose which falls rapidly whilst the hexoses remain nearly 



