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F. D. HEALD AND R. C. WALTON 
any one day. The length of time a single perithecium will continue 
to expel spores has not yet been determined. 
Effect of Alternate Wetting and Drying upon Ascospore 
Expulsion 
A test was started at laboratory temperature April 2, 1913, for the 
purpose of determining the effect of desiccation upon ascospore 
expulsion. Material from Emilie, Pa., was used and consisted of 5 
sets of specimens with 3 to a set. No. i was wet and examined every 
day, No. 2 was wet every 2d day, No. 3 every 3d day, No. 4 every 5th 
day and No. 5 every 7th day. 
The test was conducted for 42 days. The set which was allowed 
to dry one day gave by far the best expulsion. Shooting continued 
heavy to the end of the test and on the whole was considerably better 
than from the set which was wet every day. The sets wet every 
3d, 5th, and 7th day respectively gave poor expulsion. One day of 
drying gives optimum results but thereafter the longer the period of 
desiccation the fewer the number of spots. The effect of alternate 
7 5 7 5 5 7 7 60 I 37 5 47 24 47 15 19 19 19 29 34 19 23 18 
Maximum No. of Spots Obtained in One Day 
2 5 400 5 5 29 o I 4 40 18 34 14 15 I 10 15 13 15 15 II 
Percentage of Active Ostioles 
28 100 57 o o 71 71 48 o 3 80 85 75 72 93 79 5 53 52 38 79 65 61 
wetting and drying is shown by Table VII. 
Table VII 
Effect of Alternate Wetting and Drying on Spore Expulsion 
Table VI 
Expulsion from Isolated Pustules 
No. of Necks per Pustule 
Time Moistened 
Amount of Spore Expulsion 
Every 2d day. 
Every 3d day. 
Every 5th day 
Every 7th day 
Every day 
Abundant first week; moderate thereafter 
Heavy expulsion every day 
Light 
Very light 
Practically none 
