726 
Journal of Agricultural Research 
Vol. V, No. 16 
temperature at which a culture was placed, but depended also upon the 
temperature at which the organism had developed, which is, of course, a 
way of saying that the process of fruit-body formation is a process which 
depends upon the previous metabolism, and that conditions which delay 
the latter react similarly upon the former. The literature teems with 
individual facts about the temperature relation (Behrens, 1905, p. 
444-449). The temperature relation, better than any other, shows the 
significance of the cardinal points in relation to life processes. Accord¬ 
ingly, we have the generalization of Klebs (1900), that the limits per¬ 
mitting vegetative growth are wider than those permitting fructification, 
and this law is nowhere more admirably illustrated than in the tempera¬ 
ture relation. 
My early experiments with temperature are not applicable, because 
light was excluded. Experience had shown that pycnidia were formed 
at the ordinary limits of room temperature. Successful cultures on 
various sorts of media were made in the winter with the average room 
temperature, 20 to 23 0 , and in the summer with a temperature range 
from 25 to 30°, so long as the light factor was not neglected. 
A series of temperature experiments was made with the synthetic 
solution described upon page 752 in 100 c. c. flasks. These flasks were 
inoculated, and after three weeks' growth in weak diffuse light were 
subjected to the temperature indicated. 
TABr^ VIII .—Effect of temperature 
Tempera¬ 
ture. 
How obtained. 
Number 
of 
pycnidia. 
Increase in 
growth. 
# C. 
6-6 % 
Constant temperature icebox with glass doors. 
0 
Slight. 
Fair. 1 
TO“T 2, ^ t t . . . 
Located at window in cold hallway. 
+ 
Room temperature near window. 
+ 
Strong. 
Weak. 
23.* * . . 
Constant temperature incubator, outer door open, glass door closed.. 
0 
1 2 .. , 
.do. 
0 
Do. 
*)i). 
1 Pycnidia began to form after a week. 
The varying conditions in this experiment make necessary some inter¬ 
pretation for the clearing away of the apparent contradictions in the 
results. The absence of pycnidia in the 23 0 and 33 0 incubators, which 
is in seeming contradiction to the production of pycnidia in the summer 
time, or even at ordinary room temperature, was doubtless due to the 
fact that either the light was too much reduced or the air was depleted 
of oxygen. That the former influence was not operative seems likely 
from the fact that cultures standing in battery jars upon the incu¬ 
bator had at another time produced pycnidia. The incubators con¬ 
tained other cultures at the time of the experiment, and, although the 
doors were opened from time to time, the chamber had the ordinary 
strong odor of old cultures. The constant low-temperature chamber 
