522 Townsend. — The Correlation of Growth 
When the plants were kept in a constant atmosphere of 
ether derived from i cc. of ether in 200 cc. of water (Series I, 
Table X), a constant retardation was observed, although the 
plants remained alive and grew for the same length of time 
as the control-plants, viz. about six days. If a stronger 
atmosphere than the above was used, a still more marked 
Table X. 
Growth of leaves in a constant atmosphere of ether. 
Series I. I a . — 1 cc. of ether in 200 cc. of water (under bell-jars). 
Avena. \ b. — Control. 
Series II. i a . — r V cc. of ether in 200 cc. of water (under bell-jars). 
Avena. \ b. — Control. 
Temperature, 20° (constant). 
Series. 
Average 
original 
length of 
leaves of 
twelve 
seedlings. 
Average 
normal 
rate of 
growth 
of leaves. 
Average 
growth 
of leaves, 
1 st period 
in ether. 
Average 
growth 
of leaves, 
2nd period 
in ether. 
Average 
growth 
of leaves, 
3rd period 
in ether. 
Average 
growth 
of leaves, 
4th period 
in ether. 
Average 
total 
growth 
of leaves 
in ether. 
P. 
24 hrs. 
24 hrs. 
24 hrs. 
48 hrs. 
48 hrs. 
144 hrs. 
I. 
a. 
39 mm. 
16 mm. 
21 mm. 
25 mm. 
38 mm. 
12 mm. 
96 mm. 
b. 
39 » 
16 „ 
27 „ 
34 „ 
56 „ 
17 » 
134 » 
P. 
24 hrs. 
24 hrs. 
48 hrs. 
48 hrs. 
72 hrs. 
192 hrs. 
II. 
a. 
26 mm. 
1 1 mm. 
21 mm. 
66 mm. 
40 mm. 
34 mm. 
161 mm. 
b. 
26 „ 
n „ 
28 „ 
58 » 
3i >, 
17 » 
134 » 
retardation was apparent. On the other hand, if a weaker 
atmosphere of ether was used, e. g. xV cc. of ether in 200 cc. 
of water (Series II, Table X), the growth was first retarded 
and then distinctly accelerated, the younger plants being 
more easily retarded in their growth than were the older 
ones. If less than T V cc. of ether was used, no change which 
could not have been due to individual differences could be 
detected. 
