504 
F. D. HEALD AND R. C. WALTON 
The Relation of Temperature to Ascospore Expulsion 
The relation of temperature to the forcible expulsion of ascospores 
from perithecia appears to have been passed over with only brief 
consideration. In a few investigations the relation of this process 
to proper temperature conditions has been mentioned. Scribner and 
Viala (i8) stated that a temperature of 20-30 degrees C. was necessary 
for the forcible ejection of the spores of the black rot fungus, but gave 
no details of experiments upon which this assertion was based. Falck 
(8) in a discussion of the dissemination of Claviceps spores by con- 
vection currents, brings out the point that this phenomenon is least 
pronounced at cellar temperatures, and attributes this entirely to the 
lack of "Temperatur-stromungen," but unfortunately the activity of 
the process of expulsion was not taken into consdieration. It seems 
probable from oar results that spore expulsion would be much less 
active at cellar temperatures. At another point he makes the state- 
ment that temperature has a pronounced effect on the rapidity of 
spore expulsion, increasing with rise in temperature, but no record is 
given of the temperatures at which observations were made. 
No exhaustive attempt has been made to bring together the 
literature dealing with the relation of temperature to ascospore expul- 
sion in general, but it can be definitely stated that no previous work 
bearing on the relation of temperature to ascospore expulsion in the 
chestnut blight fungus has been published. 
In studying the relation of temperature to expulsion of ascospores 
of the blight fungus nine tests were carried out covering a range of 
temperature from 36.5° F. to 100° F. No expulsion was obtained 
at the lowest temperature employed but with each increase in tempera- 
ture came an increase in expulsion until the optimum, 70°-8o° F., 
was reached, beyond which expulsion gradually lessened. At 100° F. 
it had practically ceased. The nine tests were as follows: 
(a) Temperature 36. 5° -40° F. Average 38.6° F, The specimens 
were collected at Emilie, Bucks County, Pa., on Dec. 22, 1912, pre- 
pared by the method described, and the experiment started two days 
later with 21 pieces for the test and 23 for the control. The specimens 
were kept at this temperature in a cold room for 12 days where there 
was absolutely no expulsion. They were then moved to the laboratory 
where for the first three days they remained inactive, but after that 
time there was a gradual increase until at the end of two weeks all 
