STONE: CONTACT STIMULATION 467 
TABLE 12 
Showing Growth of Peas (Pisum sativum L.) in Contact with Excelsior. Average of 
Two Experiments with Eighty-two Plants'* 
Average Height of Plants (Centimeters) 
Percentage Gain 
Stems by Contact 
Normal ooo ..2. ey ee 13.07 
Contact excelsior.......... 16.66 27% 
TABLE 13 
Showing Growth of Cucumbers (Hypocotyls) (Cucumis sativus L.) in Contact with Ex- 
celstor'8 
Average Height of Hypocoty] (Centimeters) 
Percentage Gain 
Hypocotyls by Contact 
INOEmale ats oe ee oe 15.04 
ContactiexcelSions 4 Hy.5-2 16.30 8.3% 
were to a more or less extent protected from light by the excelsior. 
One of the experiments with lupines which was carried on at the same 
time behaved in a similar manner to that of corn. In one case 31 out 
of 36 of the normal plants developed leaves averaging 7 cm. in length 
while none developed in any of the excelsior contact plants—a feature 
due to the same cause, namely, to a brief and accidental exposure of 
the plants to light. 
TABLE 14 
Showing Growth of Cotyledons and Leaves of Corn (Zea Mays L.) in Contact with Ex- 
celsior. Average of Two Experiments with 72 Plants'4 
Average Length of Cotyledons and Leaves (Centimeters) 
| Percentage of Gain by Contact 
Cotyledons Leaves ze 
Cotyledons Leaves 
IN Oniiia lire, oaeee- ene oye ci 8.41 17275 
Contact excelsion= .. 2/205... : = 1007 - SF inSiag et 19% | 4% 
TABLE 15 
Showing Growth of Turnip (Hypocotyls) (Brassica Rapa L.) in Contact with Excelsior. 
Average of Two Experiments with 194 Plants 
Average Height of Hypocotyls (Centimeters) 
Percentage Gain 
Hypocotyls by Contact 
INOnmaliey shes t cerca 8.57 
Gontact/excelsion.-= 2-1. 2414 9.66 11% 
12 Experiments in which light was excluded. 
13 Experiments in which light was excluded. No. of plants used 26. 
14 Experiments in which light was excluded. 
15 Experiments in which light was excluded. 
