in the Bromes and their Brown Rust. 267 
TABLE VIII. 
N°s. 753, 694, 695, 698, 699. Experiments to test the effects of light on the 
germination of the Uredospores. 
No. 
Date. 
Origin of spores. 
Nature of 
light used. 
Direction of 
incidence. 
Temperature. 
753 a 
July 7 
B. mollis 
(1) 
Ordinary 
From below 
19-20° C 
„ b 
99 
99 
( 2 ) 
» 
From above 
>> 
a c 
99 
99 
(3) 
a 
All round 
„ d 
99 
99 
(4) 
}> 
From one side 
it 
694 a 
May 24 
B. sterilis 
( 5 ) 
it 
All round 
20 C 
„ b 
99 
99 
(6) 
» 
Light excluded 
entirely 
99 
695 a 
99 
B. mollis 
(7) 
)> 
99 
99 
„ b 
99 
99 
( 8 ) 
a 
From all sides 
99 
698 a 
May 25 
B. sterilis 
(9) 
Under blue glass 
From above 
about 16 C 1 
„ of 
}> 
99 
(10) 
» 
,, 
„ b 
» 
99 
(11) 
Under red glass 
n 
99 
„ v 
>) 
99 
(12) 
>> 
n 
99 
699 a 
99 
(13) 
Ordinary light 
From all sides 
18.5 C 
,, b 
)> 
99 
(14) 
99 
Light excluded 
a 
1 The variations of temperature seemed slight, but were not recorded continuously. 
(1-4) Germinated well in an hour, and tubes turned chiefly downwards. 
Numerous foreign fungus-spores present. In 3 hours vigorous. 
(5) In 3 hours the germ-tubes were 2-5 times the spore-diameter in 
length. 
(6) Germination not quite so vigorous but still very good. 
(7, 8) Similar results. 
(9) In 24 hours only 1 spore germinated of 58 in the drop. 
(10) In 24 hours none germinated of 114 spores. 
(11) In 4 hours tubes 5-8 times the spore-diameter in length. In 24 
hours about 150 spores of some 200 have germinated. 
(12) Germination begun in 4 hours. In 24 hours about 20 out of 120 
had germinated : drop drying up. 
(13) Several spores have tubes twice the spore-diameter in length in 
4 hours. 
(14) At least one spore germinated equally well. 
case of the light through blue glass I am inclined to suspect 
that carefully extended observations may show that the effects 
are but slight— that the orange-yellow cell contents protect 
the protoplasm from the action of the blue rays. Never- 
theless, there seems to be some slight inhibiting action worth 
further examination. The chief difficulty will be to get com- 
parative results at similar temperatures. 
My reasons for varying the direction of incidence of the 
light in certain cases were based on some results (as yet 
T 2 
