476 Mason . — Growth and Abscission in Sea Island Colton . 
It will be seen that the age of the first lot at shedding was markedly greater 
than that of the second, which in this respect was just about normal. The 
question which presents itself is, Why should the completion of abscission 
have been delayed to such an extent in the first lot ? for the stimulus to 
abscission, in the absence of fertilization, must have come into operation at 
the same time in both lots. There is little doubt that the explanation lies 
in the fact that the bolls of the first lot belonged to plants from which all 
the fruit had been removed, thus augmenting the normal supply of 
assimilates , whereas the bolls of the second lot belonged to an ordinary 
field population, which had received no treatment of any kind. The 
inference to be drawn from this experiment is presumably that the interval 
elapsing between the occurrence of the factor initiating abscission and the 
completion of the process is determined in a large measure by the supply of 
assimilates available. 
Table I. Number of Bolls shed on Successive Days after Open 
Days after 
Flower Stage. 
Lot L. Bolls. * Day after 
Lot IL. 
open flower 
Flowers and other 
open flower 
30 bolls. 
stage. 
bolls removed. 
stage. 
9 
4 
3 
1 
10 
5 
4 
— 
1 1 
2 
5 
1 
1 2 
2 
6 
5 
13 
4 
7 
10 
H 
8 
8 
15 
’ — r 
9 
4 
16 
2 
10 
1 
17 
I 
1 1 
— 
iS 
— 
12 
' — ■ 
19 
— 
13 
— 
20 
2 
H 
— 
In the course of the preceding pages, it will be recalled, the hypothesis 
was advanced that the progressive increase in the susceptibility to shedding 
resulted from the fact that the rate at which food is elaborated by the plant 
tends to lag behind the rate at which it is utilized by the developing fruit, 
and that any retardation in the rate of food elaboration results in augmented 
rates of shedding. Professor Farmer suggested that it might be instructive 
to observe the effect on shedding of cutting off the supply of assimilates. 
Exposure of plants at different stages of development to an atmosphere 
devoid of carbon dioxide for definite periods would have been the most 
satisfactory method of doing that, but the experiment was not found to be 
practicable ; removal of the foliage leaves was accordingly resorted to. 
The plants selected for the experiment had at the time a number of maturing 
bolls. A number of flowers (331) were tagged on three successive days 
and the leaves’ removed from approximately half the plants on the fourth 
day. Accordingly, at the time of the operation, the bolls ranged from one 
