292 
Journal of Agricultural Research 
Vol. XI, No. 7 
spot developed at the various temperatures in moist chambers to which 
wet filter paper had been added, and curve D the amount developed in 
open containers in an atmosphere having a relative humidity that ranged 
from 85 to 95 per cent, and usually 
stood slightly above 90 per cent. The 
weekly contrasts obtained under these 
two conditions of storage are given in 
figures 2 and 3. At 15 0 a second box 
was maintained in which the relative 
humidity ranged from 65 to 75 per 
cent, and usually stood at 70 per cent. 
Under this condition the fruit became 
decidedly withered by the end of the 
second month. The rate at which 
Jonathan-spot developed on the apples 
in the open containers in this dry box 
was practically the same as that in the 
more humid box at the same tempera¬ 
ture (fig. 3). 
A study of the results in figures 2, 3, 
6, and 8 shows that the amount of Jon- 
athan-spot in the moist chambers was 
usually more than twice as great as that in the open containers, and 
that this held not only for all the temperatures but for the various 
periods Of storage. The results seem 
to leave no question that the stor¬ 
age in moist chambers favored the 
development of the disease, but the 
nature of the experiment makes it 
difficult to estimate the relative im¬ 
portance of aeration and humidity. 
In the one experiment reported above 
in which the effect of a humidity of 
70 per cent was compared with that 
of a humidity of 90 per cent under 
similar conditions of aeration, the 
data furnished no evidence that the 
amount of moisture in the air had any 
influence upon the development of 
Jonathan-spot. In so far as the re¬ 
sults of a single experiment can be , . - - - 
, , records were taken five weeks later. 
relied upon, evidence is furnished that 
the striking contrasts obtained between storage in moist chambers and 
storage in the open containers are due to differences in aeration rather than 
to differences in humidity. This interpretation of the results would be 
Fig. 7.—Graphs showing the effect o the ma¬ 
turity of fruit on Jonathan-spot. Graph A 
shows the amount of disease on the green fruit 
and graph B the amount on the ripe fruit. The 
apples were stored in moist chambers with 
moist filter paper. The experiment was 
Stflrtpd nn flctftbpr tatp and thn oKmrp 
Fig. 6 .—Graphs showing the effect of aera¬ 
tion and humidity on Jonathan-spot. 
Graph A shows the amount of disease 
developed at the different temperatures in 
moist chambers and graph B the amount 
developed in open containers. The apples 
were large. The experiment was started 
