PLANT “RESPONSE 61 
(17° C.). I then placed it for fifteen minutes in a cooling 
chamber, temperature —2° C., for only ten minutes, 
after which, on trying to obtain response, it was found to 
have practically disappeared. I now warmed the plant 
by immersing it for awhile in water at 20° C., and this 
produced a revival of 
the response (fig. 35). 
If the plant be sub- 
jected to low tempera- 
ture for too long a 
(a) (C) 
time, there is then no 
subsequent revival. 
I obtained a simi- 
lar marked diminution 
of response with the 
flower-stalk of Arum 
lily, on lowering the 
temperature to zero. 
My next attempt 
was to compare the 
sensibility of different (b) 
plants to the effect of ‘ee 
lowered temperatures. Fic. 35.—Diinvtion or RESPONSE IN 
s Kucuaris BY Lowerinea or TEMPERATURE 
For this purpose I (a) Normal response at 17°C. 
F b) The response almost disappears when plantfis 
chose three specimens: subjected to —2° C. for fifteen minutes. 
ei (c) Revival of response on warming to 20° C. 
(1) Eucharis lily; (2) 
Ivy; and (8) Holly. I took their normal response 
at 17°C., and found that, generally speaking, they 
attained a fairly constant value after the third or 
fourth response. After taking these records of normal 
response, I placed the specimens in an ice-chamber, 
