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F. D. HEALD AND R. C. WALTON 
spore expulsion. Two trays were put in the incubator at ii :oo A. M., 
on October 27, in order to equalize the temperature but the specimens 
were not wet until 5:00 P. M. the same day. The test was continued 
for 7 days in the incubator. On the first day at this temperature 8 
traps showed expulsion averaging about 70 spots per trap. However, 
after the first day only three spots were noted and these from 2 slides 
on the last day. The abundant shooting on the first day in the 
incubator was probably due to the fact that the specimens had been 
shooting rather abundantly for two days previous to starting the 
experiment at this temperature. In comparison with the control 
which shot abundantly, there was a very light expulsion at 90.8° F. 
(see Table II). 
(i) Temperature Qy°-ioo° F. Average 98.4° F. The specimens 
were collected at Emilie, Bucks County, Pa., prepared by the same 
method as for the preceding tests, and the bark wet and experiment 
started April 2, 1913. 12 pieces of bark were used for the experiment 
proper, and 12 for the control. All of the specimens were kept at 
laboratory temperature for the first day and on April 3 half were 
put in the high temperature room and the others retained at the 
laboratory as controls. The test was continued for 15 days at an 
average temperature of 98.4° F. For the first 5 days the specimens 
were wet once a day but this was not sufiicient because of drying out 
due to the high temperature. Only two active ostioles were recorded 
during this 5-day period and those from a single specimen on the 
fourth day. After the fifth day and until the 15th, when the test 
was brought to a close, the specimens were moistened twice a day and 
not allowed to dry out. On the sixth day 8 of the traps shot spores 
but expulsion was very light, there being only 41 spots from all. On 
the 7th and 8th days three specimens showed expulsion of spores but 
there were less than 20 spots each per day. For the remaining 7 days, 
there was absolutely no expulsion. The traps were then moved to the 
laboratory and kept under observation for 22 days. For the first 14 
days there was practically no expulsion but after that they gradually 
picked up and on the last 3 days of the test every specimen shot 
rather freely. The control traps at laboratory temperature averaging 
70.3° F. showed abundant expulsion, or an average of 64.6 active 
ostioles per specimen per day, while the specimens at 98.4° gave an 
average of only 0.4 (see Table II). 
The results of the preceding tests on the relation of temperature 
to ascospore expulsion are summarized in Tables II and III. 
