32 
Journal of Agricultural Research 
Vol. VII, No. i 
parts of each fraction and not upon large single samples. The presence 
of waxy and resinous bodies in the lipoid fraction also contributes to the 
difficulty met in securing accordant results. In normal fruits 68.22 pel 
cent of the total ash is present in fractions 2, with 31.11 per cent in frac¬ 
tion 3. In half-decayed material these percentages become 78.66 and 
21.81, respectively, while when decay becomes complete 85.11 per cent is 
present in fraction 2 and only 14.89 per cent in fraction 3. There is 
clearly a steady transfer of mineral elements from insoluble combina¬ 
tions with constituents of fraction 3 into less complex, readily soluble 
forms as the disease proceeds. At the same time there is a reduction 
in the originally very small quantity of ash in the lipoid fraction practi¬ 
cally to zero, the amounts found in this fraction for wholly decayed 
fruits being uniformly too small to weigh. 
As originally planned, the present study also contemplated the deter¬ 
mination of the amounts of tannins and tannin derivatives present in 
normal and diseased fruits, to the end that some information as to the 
effect of the growth of the fungus upon these compounds might be 
secured. A review of the literature resulted in the bringing together of 
a number of methods which were tried out in a comparative way, in 
part by the authors upon apples and pears, in part by Dr. F. A. Wolf in 
the course of his work in the same laboratory upon other plant 
material (28). The results were of such discordant character as to be 
entirely valueless. It is clear that we have as yet no methods of esti¬ 
mating tannins which are sufficiently quantitative to be dependable 
when a fruit very low in tannin content is employed and when the pur¬ 
pose in view is the recognition of small alterations in this content. 
CHANGES PRODUCED BY SPHAEROPSIS MALORUM IN APPLES IN 
ARTIFICIAL CULTURE 
In order that the analytical results reported in the preceding pages 
might be compared with results obtained when pure cultures of Sphae- 
ropsis malorum were allowed to act upon mature sterile apple tissue 
under the most favorable conditions for growth obtainable in the labora¬ 
tory, a number of experiments with such cultures were made. 
On June 21 a carefully selected lot of sound, mature apples were 
ground in the manner previously described, 100-gm. samples were weighed 
into Erlenmeyer flasks, plugged with cotton, and sterilized in an auto¬ 
clave for three successive days. Half the flasks were then inoculated 
from a pure culture of Sphaeropsis malorum; the remaining flasks were 
kept as sterile checks. All were then incubated until August 15 at 
32 0 C. Dry-weight determinations upon a 100-gm. portion of the original 
material gave a weight of 12.600 gm. At the end of 54 days of incuba¬ 
tion, sterile and inoculated flasks were opened and the contents of each 
separated into the three fractions. The dry weight of each fraction was 
then determined. The results are given in Table III. 
