376 True . — < 9 ^ the Influence of Sudden Changes of 
II, so here, this normal rate is only temporary, the curve 
again beginning to sink. The transfer to water is seen to be 
followed, not immediately by a growth-rate characteristic of 
this medium, but by a retarded growth. Only after about 
20 hours has the normal rate been established. Indeed, the 
roots seem to have been permanently affected, since the 
maximum rate reached is considerably less than in normal 
roots grown in water. 
In a duplicate experiment with roots of Pisum sativum , the 
curve ran parallel to the preceding until the change to water 
TABLE V. 
Period. 
Growth per hr. 
Medium. 
Temperature. 
Hours. 
Min. 
30 
000 mm. 
1% KN0 3 
19-5° C. 
3 
30 
0-20 
yy 
yy yy 
19.6 „ 
2 
30 
0.65 
y y 
yy yy 
19-7 » 
16 
30 
0-70 
yy 
yy yy 
i 9 - 2 » 
22 
45 
0.65 
yy 
yy yy 
18-6 „ 
30 
to. 2 5 
yy 
Water 
19-0 „ 
2 
J 5 
0.10 
yy 
yy 
19-0 „ 
5 
00 
0.25 
yy 
yy 
19-0 >> i 
16 
30 
o-6o 
18.0 „ 
24 
30 
090 
yy 
yy 
i 8 -o „ 
2 4 
00 
1.05 
y y 
yy 
17-5 » 
26 
00 
1.05 
yy 
yy 
16.8 „ 
22 
00 
1. TO 
yy 
yy 
I?* 2 „ 
24 
00 
°'95 
„ 
yy 
16.5 „ 
24 
15 
0-75 
yy 
yy 
16.2 ,, 
t Estimated average elongation. 
was made. Recovery in water was not possible, and after 
five days of about one-fourth normal growth, the curve sank 
to the minimum. 
In Table V are given the growth-rates of a series of roots 
of Vicia Faba during and following an exposure of 4 6 hours 
to a 1 per cent, solution of the usual salt. The series, origin- 
