388 MacDougaL— The Mechanism of 
Sept. 27, 12.30 noon. The strain amounted to 12-5 grams. The 
temperature of the plant-house at this time rose to 27 0 C., the 
leaves of the whole plant assumed a wilted drooping position, and the 
strain at 3 p.m. fell to 11*5 grams. Four litres of water were then 
applied to the soil about the roots. After pouring on the water an 
increase of tension began, which at 3.15 amounted to 12 grams, and 
at 3.30 to 13 grams ; 6 p.m. to 14 grams ; 9 p.m. to 15 grams, which 
was the capacity of the dynamometer. The strain remained fixed 
at that point at 8 a.m. on the 28th. 
II. 
Sept. 14. A tendril of Passiflora incarnata was attached by the 
hooked tip to the dynamometer, which denoted a strain of -5 gram. 
After twenty minutes, when the strain was zero, the entire under 
surface of the tendril was stimulated by rubbing. A tension of -2 or 
• 25 gram was set up, and the organ was thrown into a number of 
curves which gave it an undulating outline. In an hour this tension 
had disappeared. 
Sept. 15, 8 a.m. The dynamometer showed a strain of -25 gram. 
The hooked tip had contracted still further, elongated and encircled 
the hook of the dynamometer. 
At 5-30 p.m. the strain had increased to -5 gram, and the tendril 
had formed a number of loose coils. 
III. 
Oct. 9, 1 p.m. A tendril of the Gourd was fastened in an inverted 
position with the tip attached to the dynamometer, with a strain of 
• 75 gram and a temperature of 30°C. 
Oct. 10, 4 p.m. Sunny Temperature 22°C. Readjusted to -5 grm. 
Oct. 1 1, 8.30 a.m. 
33 
33 
i6°C. 
T ension 
3 
33 
„ 12 a.m. 
Cloudy 
33 
25 ° C. 
33 
4‘5 
33 
„ 3 p.m. 
33 
2 2° C. 
33 
7 
33 
Oct. 12, 8 a.m. 
Sunny 
33 
1 9 0 C. 
33 
9-5 
33 
„ 10 a.m. 
33 
3 3 
20° C. 
33 
9-5 
>3 
„ 4 p.m. 
33 
33 
28° C. 
33 
10 
33 
Oct. 14, to a.m. 
33 
33 
3 2 ° C. 
33 
7 
33 
Oct. 15, 8 a.m. 
33 
33 
i 4 °C. 
33 
8 
33 
