Oct, 2, I916 
Effect of Blackrot Fungus on the Apple 
27 
The most immediately obvious fact observed upon inspection of Table 
II is the very considerable decrease in the total dry weight of solids 
recovered in the analyses of partially and totally decayed fruits. In 
comparison with a total dry weight of 12.940 gm. in normal fruits, the 
half-decayed material had 12.373 a loss of 0.567 gm., or 4.38 per 
cent, while completely decayed material had a dry weight of 12.060 gm., 
with a loss of 0.880 gm., or 6.80 per cent. When the distribution of the 
dry weight between the three fractions is considered, it is apparent that 
the progress of the disease is accompanied by a very marked decrease in 
the constituents soluble in alcohol, ether, or water and consequently 
recovered in fraction 2. These make up 78.94 per cent of the dry weight 
of the normal fruit, 75.94 per cent of the weight of the half-decayed 
fruit, and 65.14 per cent of the weight of the wholly decayed material, a 
total decrease of 13.85 per cent. This reduction in fraction 2 is accom¬ 
panied by a decrease, followed by an increase, in the lipoid material 
constituting fraction 1, and by a steady increase in the quantity of insol¬ 
uble residue (fraction 3). In half-decayed fruits, lipoids make up 4.26 
per cent and in wholly decayed fruits 6.29 per cent of the total dry 
weight, as compared with 4.82 per cent in normal tissues. There is con¬ 
sequently an absolute increase of 30.7 per cent in the lipoids as a result 
of the diseased condition. Concurrently, there is in the insoluble con¬ 
stituents making up fraction 3 an increase from 16.24 P er cent m sound 
apples to 19.80 per cent in half-decayed fruit and 28.57 per cent in 
wholly decayed fruits. With a total dry weight equaling 12.060 gm. 
for wholly decayed fruits, the insoluble residue totals 3.445 gm., while 
a total dry weight of 12.940 gm. of sound fruit has an insoluble residue 
of only 2.100 gm. Stated in summary fashion, the result of the progress 
of disease to complete decay of the tissues is an increase of the insoluble 
residue to 176.23 per cent and of the lipoid fraction to 130.7 per cent 
of the normal, with a concurrent decrease of the water-soluble portion 
of the alcohol-ether-water extract to 82.29 P er cent of normal. The 
significance of these differences will appear as the details of the analysis 
are discussed. 
The nitrogenous constituents are practically wholly contained in frac¬ 
tions 2 and 3, since fraction 1, both in normal and in decayed fruits, uni¬ 
formly gave amounts too small to be included in the tables. The total 
amounts of nitrogen found are very small, and there is a slight decrease, 
amounting to only 3.4 mgm. in an original total of 60.3 mgm., in the com¬ 
pletely decayed fruit. The significant feature of the results lies in the 
fact that there is a steady decrease in the nitrogen of fraction 2, which rep¬ 
resents proteoses, peptones, polypeptids, amino acids, and nitrogen bases, 
as the disease progresses. The amounts in this fraction are 21, 16.59, 
and 9.33 mgm. for sound, half-decayed, and completely decayed fruits, 
respectively. There is a corresponding, though not absolutely compen¬ 
satory, increase in the nitrogen of fraction 3. The figures for that fraction 
