Turgor and of Temperature on Growth. 395 
No experiments involving measurements with the scale 
were made, since, from the foregoing, it would seem highly 
improbable that the stimulus given would produce a reaction 
sufficiently great to be detected by this means. 
The experiments of Pedersen 1 tend to confirm this view. 
Roots of Vida Faba exposed to sudden and to gradual 
changes of temperature between io° and 20° R. gave no 
evidence of any retardation of growth that could be detected 
with the scale. 
TABLE XXL 
Period. 
Growth per 5 hr. 
Temperature. 
IO.25-II.25 
2-8 units 
30-0-30- 2°C. 
II. 25-I I.40 
4-5 
?? 
30-1 „ 
1 1. 40-I I.55 
3.0 
30-0 „ 
n*55 —I 2*io 
18.0 „ 
12.10-12.25 
1*0 
>> 
18.1 „ 
12.25-2.25 
2.1 
n 
17.9-18.2 „ 
2.25-2.40 
i *5 
„ 
l8-2 „ 
2.40-2.55 
2.5 
18-2 „ 
2.55-3.10 
6-o 
y> 
30*2 „ 
3-10-3.25 
4*5 
)> 
30-2-30-0 „ 
3 - 25 - 3-55 
4.0 
>> 
30-0 „ 
3 - 55 - 4 -IO 
5*5 
)> 
30-0 „ 
4.10-4.25 
i *5 
>> 
18-2 „ 
4.25-4.40 
3 -o 
>> 
18.0 „ 
4.40-4.55 
2-0 
18.0 „ 
1 unit = 0-0429 mm. 
An attempt to secure the simple effect of temperature-change, 
as such, was made in the following manner. By reference to 
a table 2 of growth-rates at various temperatures, two points 
were selected, one above the optimum and one below it, at 
which the growth-rates were approximately equal. As such 
for Vicia Faba 18 0 and 30° C. were selected. On transferring 
1 Pedersen, loc. cit. 
2 Koeppen. loc. cit., p. 40. Also Pfeffer, Pflanzenphysiologie, Bd. II, p. 129. 
