3i4 
Journal of Agricultural Research 
Vol. XI, No. 7 
example of this is seen in the curves of the Grimes apples of figures 
ii and 15. Both were of the same lot, but those of the latter figure 
had been in commercial cold storage five weeks before the particular 
experiment was started. These apples had a day's aeration in the labo¬ 
ratory and were then divided up and placed at the various temperatures 
of the experiment. Those in moist chambers at o° scalded as quickly 
as those left in commercial cold storage or as those of figure 12 that were 
placed at o° in the beginning, but those in moist chambers at io°, 15 0 , 
and 20 0 scalded far more slowly than similar apples that had never been 
in storage. (See figures 11 and 15.) The cold-storage apples placed in 
open containers did not scald at any of the temperatures, while the apples 
from cold storage did not scald at o° in open containers; those placed 
under this condition at first had 60 per cent of scald by the end of the 
experiment. (See curve 3, figure 17.) The checking effects of cold storage 
must not be overlooked, but the fact remains that apples stored at o° for 
more than one-third of the time necessary to produce scald at that tem¬ 
perature have scalded much more slowly upon removal to other condi¬ 
tions than similar apples fresh from the tree. 
Scald may be local in its effects; one side of the apple may be scalded 
and the other not; or scald spots may be scattered over the surface of 
the apple. 
The production of apple-scald has been accompanied by a reduction in < 
the sugar and acid content of the apple, by a retardation in skin 
color changes (in Grimes) and by an increase in mealiness, all of which 
might be considered as the expected result of respiration carried out 
under conditions of restricted aeration. When the aeration has been 
further decreased, scald has not occurred; but alcohol and various nau¬ 
seating odors have been produced, suggesting a high degree of intra¬ 
molecular respiration. The results seem to indicate that apple-scald is 
produced by the long-continued action of slightly abnormal respiratory 
conditions. 
Much that has been said in regard to the nature of scald has been found 
true of Jonathan-spot. The two diseases are alike in the tissue affected; 
they have similar temperature responses and are similarly affected by 
aeration and humidity and by maturity of fruit, In all these cases the 
response has been much less striking with Jonathan-spot than with 
apple-scald, but the similarities are great enough to suggest some close 
relationship in the fundamental causes of the two diseases. 
SUMMARY 
(1) Jonathan-spot and apple-scald have shown many similarities. The 
initial stages of both diseases were found to be confined to the color¬ 
bearing cells of the skin. Both rendered the apples susceptible to rot 
infections. Both were decreased by good aeration and by a fair degree 
