EXPULSION OF ASCOSPORES 5II 
or three days or expel at their maximum capacity the first day after 
the rest period. The length of this spasmodic expulsion varies with 
the specimens used. Sometimes it continues for two or three weeks 
and vsometimes for only a few days. At the end of this type of expul- 
sion comes a rest period when the specimens may either cease entirely 
or reduce expulsion to a minimum. This may continue for a short or 
long time. In one case shooting ceased entirely for 7 weeks after the 
spasmodic period, and then gradually picked up and for over 7 weeks 
shot abundantly without missing a day. Table IV shows for each 
'specimen the number of days expulsion occurred during the entire 
period, the number of days when there was no expulsion, the total 
number of spots recorded and the average number of active ostioles 
per day for the days when expulsion occurred. 
The records summarized in this table certainly indicate an almost 
phenomenal power of ascospore production by the chestnut blight 
fungus. The short period of continuous ascospore expulsion recorded 
by Anderson and Babcock (2) was but a meager expression of a most 
persistent power. These tests under laboratory conditions seem to 
point to the probabiUty that perithecial stromata under natural condi- 
tions in the field will not exhaust their power to produce and eject 
ascospores within the limits of a single season. Field tests in progress 
will shed definite light on this point. We may point to this remarkable 
power as one of the several factors that combine to make the chestnut 
blight fungus the most pernicious parasite that has ever invaded our 
forests. 
Effect of Removal of Perithecial Necks 
Three experiments were carried out at laboratory temperature to 
determine what effect the removal of the perithecial necks would 
have on the expulsion of ascospores. The tests were as follows: 
Two specimens collected at Emilie on Dec. 22, 1912, were used, one 
for the experiment and one for the control. Both had the perithecial 
necks well developed ; in fact one large piece of bark was broken into 
two parts so that the material would be in the same stage of develop- 
ment. On one specimen, every neck, with part of the stromatic 
tissue beneath, was removed with a sharp razor. The specimen was 
examined thoroughly with a strong lens to make certain that there 
were no necks remaining. On Dec. 24, 1912, at 10:00 A. M. both 
pieces of bark were wet and slides adjusted over them. On the 3d 
