5 1 6 Townsend . — Z/£<? Correlation of Growth 
which in turn was followed by a period of acceleration. 
Series III, Table I, shows neither acceleration nor retardation. 
If we now turn to Table II, it will be seen that the shoot 
was influenced by an injury produced upon the root. The 
final result of Series I, Table II, would indicate that no change 
Table II. 
Growth of leaf after root was injured. 
Series I. ( a . — 5 mm. removed from root-tip. 
Hordeum. ( b. — Control. 
Series II. j a. — Three-fourths of each root removed. 
Zea Mats, j b. — Control. 
Series III. \ a . — Entire root removed. 
Zea Mais. j b. — Control. 
Temperature, 22 0 (constant). 
j Series. 
Average 
original 
length of 
root of 
twelve 
seedlings. 
Average 
original 
length of 
shoot of 
twelve 
seedlings. 
Average 
normal 
rate of 
growth 
of leaf. 
Average 
growth of 
leaf, 
1st period 
after 
injury. 
Average 
growth of 
leaf,. 
2nd period 
after 
injury. 
Average 
growth of 
leaf, 
3rd period 
after 
injury. 
Average 
total 
growth of 
leaf 
after 
injury. 
P. 
24 hrs. 
24 hrs. 
24 hrs. 
24 hrs. 
72 hrs. 
I. 
a. 
28 mm. 
8 mm. 
20 mm. 
30 mm. 
37 mm. 
31 mm. 
98 mm. 
b. 
29 >> 
8 „ 
19 » 
38 „ 
40 » 
19 - 
97 0 
P. 
24 hrs. 
24 hrs. 
48 hrs. 
96 hrs. 
168 hrs. 
II. 
a. 
48 mm. 
29 mm. 
26 mm. 
24 mm. 
57 mm. 
123 mm. 
204 mm. 
b. 
4-8 >> 
26 „ 
25 „ 
29 „ 
7o „ 
00 
00 
00 
P. 
24 hrs. 
24 hrs. 
48 hrs. 
48 hrs. 
120 hrs. 
III. 
a. 
57 mm. 
23 mm. 
16 mm. 
17 mm. 
31 mm. 
19 mm. 
67 mm. 
b. 
56 „ 
21 ,, 
15 » 
20 „ 
39 v 
61 „ 
120 „ 
had taken place in the rate of growth, but an examination 
of the figures under the first period after injury shows a 
distinct retardation, while the figures under the third period 
indicate a slightly stronger acceleration. In Series II, Table I, 
the retardation became apparent within twenty-four hours, 
and continued for three days, followed by a period of accelera- 
tion which also lasted for three days. Series III of the 
