240 
The Philippine Journal of Science 
1916 
practically the same. At this temperature, there was no con- 
siderable checking of the rate of growth. When I ^succeeded 
in keeping the temperature constantly at 8°, growth seemed to 
be influenced slightly, but when it rose to 16°, growth was not 
appreciably different from that of the control stems at a tem- 
perature throughout of, say, 26°. Better arrangement of the 
experiment would of course effect temperature down nearly to 
the freezing point. To do this temporarily, I disjointed the 
outer tubes and fill them with shaved ice, and kept this up, 
renewing the ice constantly, for a period of two hours. The 
effect of this was to check the growth quite appreciably, and 
this effect continued, and finds expression in the growth during 
the twelve hours from 7.30 at night, May 28, to 7.30 the follow- 
ing morning. During the ensuing twenty-four hours, the plants 
which had been subject to local chilling grew faster than the 
control plants, which may be construed as merely showing that 
the effect of the treatment had been completely overcome. De- 
tails of this experiment are shown in Table IX. 
Table IX . — Effect of cold on stems of Dioscorea hirsuta. 
[Measurements of growth are recorded in centimeters.] 
Date. 
Tuber No. — 
Remarks. 
i 
6 a 
6 b 
9 
May 25-26. ........ 
18.0 
14.1 
12.5 
14.1 
May 26-27 . . . . ... 
20.6 
13.2 
14.6 
14.9 
May 27, 6 p. m., to May 28, 
6.7 
4.9 
6.6 
5.9 
Cold water turned through 6 6 
9 a. m. 
May 28: 
9 a. m- .. . 
a 161.0 
a 164. 3 
a 128. 2 
a 134. 0 
and 9; temperature at 9. 20 a. m., 
6° C. 
11. 30 a. m 
1.7 
0.6 
1.5 
1.3 
Room temperature at 10.30 a. m.. 
1. 30 p. m 
0.9 
0.7 
1.4 
1.0 
26° C. Water slowed at 12 m., 
temperature then, 8°. 
Temperature at 1 p. m: Room, 
3. 30 p. m . .. 
1.3 
0.8 
0.7 
0.9 
28°; 6 b, 16°: 9, 19°. 
Temperature at 3 p. m.: Room, 
6. 30 p. m . . . 
1.3 
0.7 
0.8 
1.0 
27°; 6 b and 9, 8°. At 3. 15 flow 
was checked in 9, temperature, 
16°; corrected, dropped to 8°. 
Temperature at 4. 20: Room, 28°; 
7. 30 p. m 
0.9 
0.3 
0.3 
0.6 
6 b and 9 (outflow), 8°. 
Shaved ice put in place of cold 
May 29, 7. 80 a. m 
4.6 
2.3 
1.1 
2.1 
water, 5. 30 to 7. 30; temperature 
then about 3°. Room temper- 
ature at 7. 30 was 27. 5°. 
May 30, 7.30 a. m — 
8.9 
8.1 
10.6 
11.5 
May 31, 5 p. m . . .. 
8.6 
7.7 
15.3 
8.1 
June 6, 10 a. m 
31.6 
21.9 
65.3 
46.8 
* Total length at 9 a. m.. May 28. 
