INTERNAL BROWNING OF YELLOW NEWTOWN APPLE. 19 
greatest quantity of carbohydrate, as obtained by girdling the 
branches and thinning the fruit, tended most to browning. 
When the analyses presented in Table 6 are studied, however, it 
is evident that there is a considerable variation in the acid and 
sugar content of the fruit from different trees, without a correspond- 
ing variation in the extent of browning that developed. For ex- 
ample, even the fruit from defoliated branches from tree No. 134 
was higher in sugar content than fruit from girdled or normal 
branches from either tree No. 151 or tree No. 136. Within the in- 
dividual tree, the apples from the girdled branches, running high 
in sugar and acid as compared to normal for the tree, have shown 
a marked tendency toward browning, but there is no evidence to 
indicate that trees that normally produce fruit with high sugar 
content also produce fruit with a marked tendency toward browning. 
The analyses presented in Table 6, considered in connection with 
other unpublished data on apple analyses, indicate that there may 
be a wide variation in the chemical composition of the fruit from 
different trees in an orchard and from year to year from the same 
tree. The results obtained by girdling and defoliating indicate 
that the browning of the fruit in storage is associated with condi- 
tions that produce high sugar and acid content for that tree, but | 
not that trees normally producing fruit of high sugar and high 
acid content tend to produce fruit with a greater tendency to brown- 
ing than trees that normally produce fruit of low sugar content. 
In fact, the evidence available at the present time indicates that 
the greatest tendency to browning occurs in trees which normally 
produce fruit of rather low sugar content. 
From a consideration of the foregoing data, it appears to be 
established that internal browning of apples in storage results from 
certain conditions within the tree. These conditions are not fixed, 
in the sense of being constant or hereditary, for a tree may produce 
fruit that browns badly one year and be almost free from browning 
the year following. Rather than being a tree characteristic, brown- 
ing of the fruit in storage seems to occur when certain conditions 
arise within the tree. The experiments on girdling and defoliating 
indicate that these conditions may be present in one part of the 
tree, being restricted to certain branches, while the fruit on the 
tree as a whole remains fairly sound. The fact that in these ex- 
periments sound apples were very often found in lots of fruit 
from a single tree, though in some cases almost the entire crop would 
be classed as affected with bad browning, indicates that the condi- 
tions that bring it about are even much more localized than the 
individual tree. The evidence accumulated during the course of 
these investigations gives strong indication as to what may be the 
conditions in the tree conducive to browning. 
