34 THE AMERICAN NATURALIST. [VOL. XXXIX. 
Experimentatton. 
The plants used in these experiments were prepared as in the 
preceding series, then fixed on klinostats with stems radial to 
the horizontal axes of rotation. One half of the number used 
were inclined 9o degrees, the other half, 135 degrees from the 
vertical, and both sets were held in position for a time somewhat 
shorter than the previously determined latent period for geo- 
tropic curvature in the species used. The subsequent influence 
of gravity was then removed by rotation on the klinostats for a 
time at least twice as long as the period of stimulation, and 
finally, the pots were set upright and the amounts of curvature 
made by the plants of the two groups were carefully compared. 
The number of individuals, as well as the number of species 
used in these experiments was smaller, and the results obtained 
were less satisfactory than in the experiments by the method of 
“alternating stimulation," but when any difference in after- 
effects could be observed, it was in agreement with the results 
of the alternation experiments. Ageratum, Lobelia, Chrysan- 
themum, and the seedlings of Linum showed greater curvature 
as the after-effect of stimulation at the angle of 90 degrees 
from the normal position than at 135 degrees. 
Table II. Results by After-effect Method. 


Material. Temper- Latent Time of Time of Greater Curvature 
ature. Period. Exposure. | Rotation. for Deviation of 
Young plants. 
Lobelia 25.59 C | 30 min. 20 min. | 40 min. 90 degrees 
Ageratum 22.09 C | 20 “ ry * 40 ^ go ^ 
Chrysanthemum | 22.09 C | 30 “ +| 30 “ 60 * 90 ^ 
Seedlings. 
Linum HSCs * +) dg" Codes go Oe? 







