Apr. 14,1923 Internal Browning of the Yellow Newtown Apple 
167 
As internal browning affects the flesh of the fruit, it was necessary to 
cut the apples in order to make observations upon their condition. The 
apples were cut perpendicularly to the axis of the core in a plane which 
passed approximately through the junction of the carpels wiSi the stem. 
By cutting in this plane the browning was always detected, if present. 
Obs^ations upon the browning were made at monthly intervals 
beginning with February 2 for the 1919-20 season and with January 8 
for the season of 1920-21. Twenty specimens from every sublot were 
cut at each of the four seasonal cuttings. By cutting several hundred 
apples on numerous occasions it was found that the error of observation 
in cutting only 20 specimens ranged from 2 to 5 per cent. When the 
results for the four seasonal cuttings were averaged, this error was 
reduced to i to 2 per cent. In recording the observations the following 
terms were used to designate the degree of browning: 
1. Normal, —^No browning apparent to the unaided eye; less than o.i 
per cent of cells affected. (PI. i, A.) 
2. Track browning. —^Browning recognizable in the torus but not of 
sufficient intensity to lessen the market quality; o.i to 0.6 per cent of 
cells affected. (PI. i, B.) 
3. Si/iGHT BROWNING. —^Browning in a sufficient degree of intensity to 
lessen the market quality of the fruit but not to such a degree as to make 
the apples objectionable for culinary purposes; 0.6 to 10 per cent of cells 
affected. (PI. i, C.) 
4. Moderate browning. —Browning of such an intensity as to render 
the apples unsuitable for ordinary culinary purposes. At this stage of 
browning the tissue was more generally discolored throughout the torus, 
from 10 to 30 per cent of the cells being brown. (PI. i, D.) 
5. Severe browning. —^This term refers to a degree of browning 
which upon cutting gave the apples an appearance of being rotten within. 
In these apples the structure of the tissue exhibited a marked degree of 
disintegration in all portions of the specimen; 30 per cent or more of the 
cells affected. (PI. i, E.) 
PRESENTATION OF DATA 
RELATIVE degree of INTERNAL BROWNING EXHIBITED BY YELLOW 
NEWTOWN apples GROWN IN THE PAJARO VALLEY AND ELSEWHERE 
During this study apples were also obtained from other localities in 
California and from important districts in other States where this variety 
is successfully grown to determine whether or not the browning was 
confined solely to apples grown in this valley. All of the fruit was 
shipped to Berkeley by express and was then stored at o® C. under the 
same conditions as the fruit from the Pajaro Valley. 
The figures obtained in these tests indicate that Yellow Newtown 
apples generally are more or less susceptible to internal browning. The 
disease in apples from points other than the Pajaro Valley, however, has 
not been sufficiently severe to render it an economic problem. 
The fact that all the apples showed browning would seem to indicate 
that either something peculiar to the variety makes it susceptible to 
browning or that the trouble lies in the regions in which it is at present 
most extensively grown. Both of these conditions appear to be more or 
less responsible for the browning. The fact that other varieties of apples 
grown in the same districts, with the exception of the Pajaro V^ley, 
are immune to this disease would at least suggest that the Yellow New- 
