268 Ward ’ — On Relations between Host and Parasite 
inconclusive) that the germ-tubes exhibit heliotropic curva- 
tures : this question demands closer inquiry. 
It will also be seen from the Table that the spores germinate 
in the dark as well as in the light, a fact already known for 
such fungi in general. 
Another set of experiments was made with the intention 
of seeing if any suggestive results were obtainable when some 
chlorophyll-bearing organism was present among the germi- 
nating spores. The positive results (Table IX) have a certain 
value, but I think that with the experience now obtained, it 
might be possible to design experiments more conclusive in 
nature. The Alga employed was found in a flask of Knop’s 
solution in my laboratory, and was apparently the palmella 
form of a Chlamydomonas not determined. 
TABLE IX. 
Exp. No. 701. Results of cultures in presence of a chlorophyll- 
bearing Alga compared with the same in absence of the Alga. 
No. 
Date. 
Origin of Spores. 
Alga. 
Nature of 
illumination. 
Temperature. 
701 
May 26 
B. mollis ( 1 ) 
Absent 
Ordinary light 
17-5° C 
,, a 
JJ 
„ (2) 
Present 
Under red glass 
23C 
„ a' 
„ ( 3 ) 
>> 
yy 
Under blue glass 
yy 
„ * 
)> 
„ ( 4 ) 
>> 
yy 
*, v 
yy 
( 5 ) 
a 
yy 
y y 
„ c 
yy 
„ (6) 
yy 
Ordinary light 
i7’5- l8 *5 
„ d 
„ ( 7 ) 
yy 
Darkness 
i 7 _i8, 5 
( 1 ) Germinated well in 4 hours. 
( 2 - 5 ) None germinated in 4 hours, but in 24 several spores had 
put out tubes : ( 4 ) and ( 5 ) less vigorous. 
(6) In 4 hours about 10% had tubes 4-6 times spore-diameter in 
length. 
( 7 ) In 4 hours about 50% had tubes 8-10 times the spore- 
diameter in length. 
The net result is to show that the presence of such an Alga 
is not an important determining factor, for even under blue 
glass the spores sometimes germinated during the night. It 
should be noted that at the time these experiments were made 
I was not yet in possession of the facts concerning the critical 
temperatures, nor fully alive to the necessity of choosing 
recently ripened spores, and possibly other factors of im- 
