Oct. 2, 1916 
Effect of Blackrot Fungus on the Apple 
29 
a decrease of water-soluble phosphorus to 57.89 per cent, which is 
practically the proportion found in normal tissues, and an increase in 
fraction 3 to 17.11 per cent, as compared with 12.53 per cent in sound 
fruits. Here constructive processes are predominant; a portion of the 
lipoid phosphorus, together with that derived from destruction of the 
host proteins, has been utilized in the construction of new and complex 
material, presumably protein in nature, by the blackrot organism. We 
therefore possess, in the analytical data fox nitrogen and phosphorus, an 
index to the character and amount of the changes in nitrogenous con¬ 
stituents of the fruit brought about during decay. While no attempt 
to do so has been made in this case, it would appear that a quantitative 
estimation of the several phosphorus-containing groups and a determina¬ 
tion of the relative amounts of proteoses, peptones, and amino acids 
present at various stages of the progress of the disease would contribute 
much to our knowledge not only of the changes wrought in the host 
proteins by the attacking fungus, but also of the extent to which these 
materials are wholly destroyed or utilized in constructive processes 
by the parasite. Such determinations will be attempted by the senior 
author, who contemplates continuing the work here reported. 
The most obvious changes in carbohydrate contefit are those occurring 
in fraction 2, which contains reducing sugars, disaccharids, trisaccharids, 
and glucosids, and in fraction 3, which contains the insoluble carbohy¬ 
drates, as starch, cellulose, and cellulose derivatives. The reducing 
sugars in fraction 2 are reduced from 0.574 gm. in normal fruit to 0.1619 
gm. in half-decayed fruit, and to 0.0609 gm. in wholly decayed tissue; in 
other words, there is a loss of 89.4 per cent of reducing sugars with the 
progress of the disease. Disaccharids, which total 4.960 gm. in normal 
apples, are reduced to 3.651 gm. in half-decayed fruit and to 2.234 gm. 
in wholly decayed fruits, a loss of 56.94 per cent. The data obtained 
from the determinations of acidity will be discussed later. It may be 
said here, however, that the acid content of the sound fruit, which equaled 
0.9288 per cent, calculated as malic, was reduced to 0.3563 per cent in 
the wholly decayed fruit. The steady decrease in sugar content is 
accompanied by an even larger proportional decrease in acid content, 
since 71.64 per cent of the acid of sound fruits had disappeared con¬ 
currently with a loss of 89.4 per cent of the reducing sugars and 56.94 
per cent of disaccharids. 
There is also a reduction in the amount of lipoid sugar in fraction 
1 as decay proceeds. The first determinations of sugar in this fraction 
were vitiated by the fact that sufficient precautions were not taken to 
remove the last traces of chloroform. When the senior author attempted 
to repeat the determinations upon portions of the lipoid fraction which 
had been reserved for the purpose, he encountered further difficulties. 
When a 24-hour hydrolysis with 4 per cent of hydrochloric acid is carried 
