STONE: CONTACT STIMULATION 465 
were planted, to a height of about Io inches and often less, depending 
upon the nature of the plant in use. The excelsior was cut in lengths 
varying from 1 to 10 cm. or according to the nature of the plant 
employed. Since these experiments were all made in darkness and 
the plants were in all cases covered with receptacles, such factors as 
light and transpiration were controlled, and under these conditions 
the seedlings were dependent largely on the reserved material con- 
tained in the seeds. There was, however, no contact of the plants with 
each other. Moreover in this series, the same contact material was 
used throughout, namely excelsior, and any specific reaction which 
might arise from the use of different materials in contact with the 
TABLE I0 
Showing Growth of Horse Beans (Vicia Faba L.) in Contact with Excelsior® 
Average Height and Weight in Centimeters and Grams 
Experiments | # Porriiage Gan by 
No. of Plants F : 
ees Height Weight * 
Height Weight 
(a a Normalee 9: see souk 149 14.03 0.96 
Contact excelsior....... 18.20 1.28 29% 33% 
(py miNormaless i: Se alk. 374 15.10 0.74 
Contact excelsior....... s 18.50 1.05 18% 41% 
Mone IN Ontiiall crs. shay eee [Gree 1.37 | 
, I22 | 
Contact excelsior....... | 20.41 bf Om 77/7, 9% 
Average mormal: ..5cj550 0-6 15.48 1.02 | 
OIPACE Jo the he ie | 19.03 F631.” | 23%. 3. 5870 
TABLE II 
Showing Growth of Hypocotyls of Lupines (Lupinus albus L.) in Contact with Excelsior. 
Average of Two Experiments with 128 Plants 
Average Height of Hypocotyls (Centimeters) 
Percentage Gain 
Hypocotyls by Contact 
IN ODI testi hi teie tw ache ee 19.28 
Contact excelsior.......... 21.65 12% 
plants would not be present in these. There would of course occur 
variations in the stimulus imparted to the different species owing to 
difference in the relative degree of contact of the plants with the 
excelsior—a feature which would be determined by the fineness, 
compactness and amount of the excelsior employed, as well as by the 
10 Experiments in which light was excluded. 
11 Experiments in which light was excluded. 
