Allen and Jolivette—Light Reactions of Pilobolus. 585 
In our next series of experiments, the blue glass was placed 
at one opening and the yellow glass at the other. With the 
culture two centimeters from the yellow glass more than half of 
the sporanges were fired toward the blue, although it was eigh¬ 
teen times as far away as the yellow light. With the culture in 
the middle of the box, 91% were discharged toward the blue, 
and at 22 centimeters from the yellow light all the sporanges 
were fired toward the blue. The decrease in the percentage of 
sporanges reaching the yellow glass was very irregular, prob¬ 
ably because of inequalities in the distribution of the sporanges 
on the surface of the cultures. The exact data for each observa¬ 
tion are given in Table XVI. The curve (Figure 18) is 
plotted from these data and shows the proportion of sporanges 
fired toward the bine and yellow glasses respectively. 
Table XVI —‘Culture at distances indicated. Opening 2 cm. in diameter. 
Blue and yellow glasses at opposite ends of the box. 
Distance from blue. 
4 cm. 
6 cm. 
8 cm. 
10 cm. 
12 cm. 
14 cm. 
Number on blue.. 
54 
36 
18 
10 
28 
177 
Per cent, on blue. 
100 
100 
100 
100 
100 
100 
Distance from yellow. 
34 cm. 
32 cm 
30 cm. 
28 cm. 
26 cm. 
24 cm 
Number on yellow. 
0 
0 
0 
0 
0 
0 
Per cent, on yellow. 
0 
0 
0 
0 
0 
0 
Distance from blue.... 
16 cm. 
18 cm. 
0 cm. 
22 cm. 
24 cm. 
26 cm. 
Number on blue. 
20 
80 
211 
72 
52 
Per cent, on blue. 
100 
88.2 
91.34 
75.78 
96.29 
95.24 
Distance from yellow. 
22 cm. 
20 cm. 
18 cm. 
16 cm. 
14 cm. 
12 cm. 
Number on yellow. 
0 
4 
20 
23 
2 
3 
Per cent, on yellow. 
0 
11.7 
8.65 1 
1 24.21 
3.70 
4.76 
Distance from blue. 
28 cm. 
30 cm. 
32 cm. 
1 
34 cm. 
36 cm. 
Number on blue. 
38 
29 
61 
19 
55 
Per cent, on blue. 
100 
63.04 
68.54 
70.37 
55.64 
Distance from yellow. 
0 cm. 
8 cm. 
6 cm. 
4 cm. 
2 cm 
Number on yellow.. 
0 
17 
28 
8 
69 
Per cent, on yellow. 
0 
36.95 
31.46 
29.62 
44.35 
As in the experiments with blue and white lights, the accu¬ 
racy of aim toward either the blue or the yellow did not seem to 
be affected by the presence of the other color. 
We next tried the effect of placing the copper sulphate and 
bichromate solutions at opposite ends of the box. On com¬ 
parison of the results with those when the blue and yellow 
glasses were used, a difference is found in that at two centime¬ 
ters from the bichromate solution only a small percentage of the 
