PEIRCE: ForciBLE DiscHARGE OF ANTHEROZOIDS 375 
mined to watch the plants out of doors as well as in the labora- 
tory during the following season. 
On January 20 of this year (1902) I thought the plants of 
Asterella Californica were in proper condition for testing whether 
they do or do not discharge their antherozoids under the condi- 
tions prevailing out of doors, and I set some glass slides to catch 
antherozoids if any should be expelled. A word may be said as 
to the weather and the place, as well as the manner and the result, 
of my experiment. The rains came early this season, in October 
and November, the season being ahead of the average when De- 
cember began. There was no more rain to speak of till January | 
18. On December 11 the weather became decidedly cooler 
and remained cool, with frequent white frosts at night for weeks. 
There have been heavy dews and heavy fogs at night, some of 
the fogs being so heavy as to wet the streets enough to make the 
Surface sticky. The days had been sunny as a rule, but there 
had been little growth and development among plants. In conse- 
quence, As¢ere//a is not so far along as usual at this time. The 
bank where Astere//a grows is sandy, steep, more or less covered 
with grass, shrubbery, mosses and liverworts, about half a mile 
from this university, and faces northeast, receiving little direct 
sunshine. On the morning of January 18 I was struck by the 
dryness of the soil there compared with last year. We had 20 
mm. of rain the following afternoon and night; the sun shone 
brightly and the air was warm on the 19th. The plants were 
then in perfectly normal, healthy condition on the morning of the 
2oth, after a night of heavy dew and comparative mildness. 
The sun was shining brightly, the air was rapidly growing 
warmer, as I set my slides at various distances from male plants 
of Asterella. The slides had been cleaned and numbered, and 
were held in place by wire holders thrust into the soil. The slides 
did not touch the plants and were in various positions, some hori- 
zontal, others oblique or vertical, corresponding to the positions of 
the plants. Slide no. 1 was 2~3 cm. from a patch of young 
Asterella growing on a vertical part of the bank. Other slides. 
_ Were nearer, others much further from the plants, from 0.5 cm. 
toI5cm. I put out the first slides at 10.15 a. m., the last one at 
Il. At 4.30 p.m, I took a microscope out to the bank and looked 
