106 BOTANICAL GAZETTE [FEBRUARY 
In the second experiment, with the center of the openings 4 cm. 
apart, 19 sporangia struck the glass; 1o were on the left opening, 
7 on the right. Of the remaining 2 sporangia, 1 struck in each of 
the 1-cm. strips to the left and right of the left opening. 
The third experiment shows a total discharge of 63 sporangia. 
Of that number 16 struck the left opening and 20 the right opening; 
27 failed to reach either opening, but all of that number, excepting 
3, were within 1 cm. of the opening. 
When the distance between the openings was 14 cm., ‘6 spo- 
rangia were discharged, 15 striking each of the openings; 6 sporangia 
were counted within the first 1-cm. strip to the left of the left 
opening, and 1 in the third strip; 3 and 2 were within the first and 
second strip to the right of that opening; 5 sporangia struck within 
the 1-cm. strip to the left of the right opening, and 2 and 1 in the 
first and second strips on the right-hand side. 3 
With a distance of 27 cm. between the two openings, 200 sp0- 
rangia were discharged on the glass, 61 and 37 striking the respective 
openings to the left and right. The majority of scattered sporangia 
are again grouped around the two openings. The data for these 
experiments are tabulated in complete form in table III. 
The results of the experiments in which the distances between 
the openings were varied agree with those obtained in the preceding 
set of experiments, where the openings were kept at the same dis- 
tance throughout the set of experiments. The sporangia were 
fired with great accuracy toward one or the other of the two open- 
ings. The distribution of the sporangia about the openings varied 
in about the same degree as in the case just mentioned; and in the 
same way, the sporangia which are outside the vertical strips con- 
taining the openings are mostly within 1 cm. of one of the openings. 
The reaction of Pilobolus when stimulated simultaneously by 
lights of different wave-length 
The problems connected with the simultaneous stimulation of 
an organism by light rays of various wave-lengths offer an interest- 
ing field to the investigator. But I know of no way of accurately 
comparing lights of different colors as to the total amounts of 
