478 Kidd and West . — The Controlling 
which was found to be established in the embryo during secondary 
dormancy. The occurrence of a time factor is interesting since it indicates 
that the changes involved, by which dormancy is removed, are secondary 
to the changes involved in drying. In . this connexion it should be 
remembered that an interval of time, pointing in all probability also to 
the occurrence of secondary changes in the saturated embryo, was found 
necessary for the production of secondary dormancy, as shown in section 1. 
When seeds are set on wet sand in the presence of inhibiting gas mixtures, 
growth and germination are inhibited from the beginning, but the condition 
of secondary dormancy is not established for several days. 
It was found that the redrying of inhibited seeds has a further effect 
upon the embryo beyond that of destroying the condition characteristic 
of secondary dormancy. In comparing the germination of redried inhibited 
seed with that of control seed, the germination of the redried seed was 
invariably quicker and more vigorous in the initial stages than that of the 
control seed. Further experiments in which redried inhibited seeds were 
compared with control seeds, redried after fifteen hours’ soaking, showed 
that this acceleration is a result of the redrying of the seeds and is not 
Table XIX. 
The Accelerated Germination of Redried White Mustard Seeds. 
Experiment. Germinations after — 
26 hours. 48 hours. 70 hours. 
Control ; fresh seed. o 8 10 
Redried inhibited seed. 9 10 10 
Redried non-inhibited seed. 9 10 10 
Redried inhibited seed. 9 10 10 
10 seeds used in each experiment. Temperature = 1 8° C. In light. 
connected with previous inhibition or with secondary dormancy. The 
redrying of soaked seeds appears to act as a definite stimulus. In the 
case of control seeds redried after soaking, a varying proportion showed 
at the same time visible injury to the radicle. A second swelling and 
redrying increases this proportion. Further, if germination has occurred, 
redrying invariably kills the radicle. The case of redried inhibited seeds 
is in contrast to this. It is to be emphasized that when redried inhibited 
seeds are set to germinate all the radicles develop in a perfectly healthy 
and normal manner. Inhibition and secondary dormancy can be induced 
a second time. Redrying will again destroy the dormant condition. The 
radicles, however, still all remain healthy and normal. From these facts 
it may be concluded : (i) that redrying of fully swollen normal seeds at an 
early stage of development previous to germination results in an accelerated 
germination when the seeds are subsequently resown ; (ii) that redrying of 
