208 Ingvar Jorgensen and Walter Stiles. 
assimilation.” However, it is not clear how Brown and Morris’s 
work leads to this conclusion. The hexoses of the Z-series are not 
fermented by yeasts and there is no evidence in Brown and Morris’s 
paper that these workers tested for hexoses of the Z-series after the 
rZ-hexoses had been fermented away. Davis and Sawyer, on the 
other hand, show that if this is done there still remain cupric- 
reducing and optically active substances which they conclude are 
pentoses, and they seem inclined to regard them as a mixture of 
Z-arabinose and Z-xylose, and they support this contention with 
determinations of pentoses by the Krober-Tollens method in the way 
we have already described, but without showing any great concord- 
Table XXVI11. 
Carbohydrates of the Leaf. 
Group. 
Compound. 
Evidence of Presence. 
Polysaccharides’ 
Starch 
Test with Iodine Solution (Sachs). 
Hydrolysis with Diastase (Brown and Morris) or 
with Taka-Diastase (Davis, Daish and Sawyer). 
Pentosans 
Leaf matter insoluble in alcohol yields furfural on 
distillation with concentrated hydrochloric acid 
(Davis, Daish and Sawyer). 
Dextrin 
Leaf matter insoluble in alcohol but soluble in water 
which possesses optical activity and reducing 
properties after treatment with taka-diastase 
occurs sometimes in Potato (Davis and Sawyer). 
Disaccharides... 
Sucrose 
Extracted by Kayser from Vine leaves. 
Inverted with invertase and weak acids (Brown and 
Morris). 
? Maltose 
Production of maltose phenyl-osazone from leaf 
extracts (Brown and Morris). 
Microchemical test by production of osazone. 
Presence denied by Davis, Daish and Sawyer. 
Hexoses 
d-Glucose | 
d- Fructose j 
Cupric reducing power of plant extracts. 
Production of glucose phenyl-osazone from plant 
extracts (Brown and Morris, Parkin). 
Pentoses 
? /-Arabinose j 
? /-Xylose j 
Purified alcoholic extracts of leaves yield furfural 
on distillation with concentrated hydrochloric 
acid (Davis and Sawyer). 
Presence denied by Brown and Morris. 
1 Exclusive of cellulose and pectin substances. 
