34 
Journal of Agricultural Research 
VoJ. VII, No. i 
Comparisons of the carbohydrate content of artificial cultures with 
sterile checks were made upon material collected June 27, when the fruits 
had become fully ripe and somewhat soft. Four identical 100-gm. 
samples were prepared from one lot of pulp, sterilized for three suc¬ 
cessive days, and two were then inoculated while two were kept as 
sterile checks. All were incubated for 42 days. One each of the inocu¬ 
lated and the sterile flasks were then opened and the contents extracted 
for 12 hours with 95 per cent alcohol, the other pair being extracted 
for the same period with water. After the removal of the noncarbo¬ 
hydrate material from the extracts, determinations of the reducing and 
nonreducing sugars were made by the methods previously described. 
The results are summarized in Table IV. 
Table IV. —Carbohydrate content {in grams) of water and alcohol extracts of sterile 
checks and cultures of Sphaeropsis mahrum upon apple pulp after 42 days’ incubation t 
100 gm . of finely ground pulp in each flask 
* 
Extract. 
Reducing 
sugars. 
Nonredudng 
sugars. 
Total sugar 
after 
hydrolysis. 
Water extract: 
Sterile check. 
1.736 
0. 328 
2. 064 
Inoculated. 
.960 
• * 33 6 
I. 0936 
Alcohol extract: 
Sterile check.. 
7.496 
. 1427 
7. 638 
Inoculated. 
2. 128 
.068 
2. I96 
Alcohol extraction recovered from the sterile check a total of 60.62 
per cent of the original dry weight as sugars, and from the inoculated 
material only 17.42 per cent, a difference of 43.20 per cent, or 5.442 gm. 
in an original dry weight of 12.600 gm. That monosaccharids are rapidly 
attacked by the fungus while disaccharids are much more slowly re¬ 
duced is indicated by the data of Table VI as well as by that presented 
in Table II. 
Since Sphaeropsis malorum obtains the energy necessary for its growth 
mainly from the oxidation of carbohydrates, an attempt was made to 
secure information as to the nature of the products resulting from carbo¬ 
hydrate decomposition. Determinations of the acid and alcohol content 
of fruits in various stages of decay from blackrot, with check determina¬ 
tions upon sound fruits, were carried out. 
ACIDITY OF NORMAL AND DISEASED APPLES 
Sound, partially decayed, and wholly decayed apples were selected 
and material was prepared and ground exactly as in the preparation of 
other samples. Duplicate 40-gm. portions of each lot were weighed 
off, each portion was placed in a 500 c. c. flask, and 200 c. c. of distilled 
water added thereto. One set of flasks was then placed on a water bath 
and kept at ioo° C. for four hours, the duplicate set meanwhile being 
kept at room temperature. All were thoroughly shaken at short intervals. 
