228 Ingvar Jorgensen and Walter Stiles. 
that the sucrose is translocated away from the leaves in the form 
of hexoses. 
Even in this plant where the leaves contain abundant starch 
no maltose is found, either in the leaves or petioles. Davis and 
Sawyer therefore conclude that the starch, on utilisation by the 
plant, is broken down into hexoses by a mixture of enzymes similar 
to that of Aspergillus oryzce which yields taka-diastase. They 
consider that dextrin and maltose are intermediate stages in the 
degradation of starch to glucose. Dextrin indeed appears at the 
period when starch is in large quantity in the leaf. They suppose 
the enzyme maltase is always present in relative excess in the leaf, 
and Daish (1916) has shown the presence of maltase in a number 
of different leaves. 
5. Vine (Vitis vinifera). 
In the leaf of the vine, a plant which stores its carbohydrate 
as glucose, Deleano (1912) was unable to detect sucrose in the leaf. 
Davis and his co-workers, on the other hand, state that after taking 
special precautions in sampling to prevent the leaf enzymes from 
acting, sucrose is found to be the principal sugar of the leaf. This 
they regard as supporting their view that sucrose is the first sugar 
formed in assimilation. 
F. Carbohydrate Transformations in the Leaf. 
The pioneer researches of Sachs indicated the formation of 
starch in the chloroplasts of the leaf as a result of carbon assimilation, 
and it was this investigator who showed the dependence of starch 
formation on light and chlorophyll. The proof was completed by 
Godlewski (1873) and Pfeffer (1873) who showed the necessity for 
an outer atmosphere containing carbon dioxide. 
Sachs held the view that starch was the first visible product of 
assimilation, and he bound himself to no theories concerning 
possible intermediate products in its formation. 
Kayser’s work (1883) established the presence of sucrose in 
the leaf of the vine. It was supposed that starch was converted 
into cane sugar by diastatic enzymes and that the cane sugar was 
inverted in the conducting tissue of the leaf. Sachs (1884) also 
expressed the opinion that the starch is translocated in the form of 
sugar. 
That starch could not always be the first visible product of 
carbon assimilation became obvious from the researches of A. Meyer 
(1885) who showed that different species varied greatly in their 
