EFFECTS OF BROWN-ROT FUNGUS UPON PEACH 
75 
crystallized out. After several recrystallizations this sugar was iden- 
tified as sucrose by its melting point, by the fact that it did not reduce 
Fehling's solution until after inversion with acid or invertase and by 
its specific rotation. 
As has been said, the alcoholic sugar solution was filtered off the 
peach sample and the amount of sugar determined in the filtrate. 
The residue on the filter was carefully removed to a porcelain extrac- 
tion thimble and extracted for one day continuously in a Soxhlet 
extractor. It was then dried, ground up and treated according to 
the usual routine for the determination of starch. The determinations 
were made by the direct acid hydrolysis method (8), as in the case of 
the sugars. Whether any considerable amount of these substances, 
which aie insoluble in alcohol and reduce Fehling's solution after 
hydrolysis with dilute hydrochloric acid, are starch, is an open ques- 
tion. Bigelow and Gore (2) found starch grains in young peaches 
located only in a thin layer just under the epidermis. Determined 
quantitatively they found only one tenth of one per cent. The 
present writer examined portions of the ground pulp microscopically 
and, while bodies were present which gave the blue color with iodine, 
no definitely formed starch grains were discovered. 
To obtain more evidence upon this point, six twenty-five gram 
samples of peach pulp were weighed out and extracted. After 
drying, three of the samples were treated by the direct acid hydrolysis 
method and the reducing substances determined in the usual way. 
The other three samples were carefully ground with fine sand and 
then digested with malt diastase and treated as in the diastase method 
for the determination of starch (8). The reducing substance was 
determined as m the other three samples. A comparison of the 
percentage of reducing substance in the two sets of samples, calculated 
as starch, is given below. 
From the results of these determinations it seems that a portion 
of alcohol-insoluble substance which reduces Fehling's solution after 
hydrolysis with dilute hydrochloric acid, is either starch or some 
compound, such as dextrin, which is liquefied by diastase. The 
present work and the investigations of Bigelow and Gore would seem 
Acid Hydrolysis 
Diastase Method 
1.24 
1-33 
1-34 
0.32 
0.38 
0.37 
