224 BOTANICAL GAZETTE [MARCH 
The preceding table expresses the results of some 300 separate 
. determinations in which over 15,000 seeds were used. Each 
time interval was repeatedly verified, and since in some cases 
exactly corresponding results could not be obtained, an average 
was in such cases taken. The duration of life of the seeds was 
taken to be the time in minutes for which a given temperature 
must act in order to inhibit the subsequent growth of all the 
seeds when placed under the conditions above described. it 
The temperature coefficient of the duration of life of barley granis 
has been determined for the temperatures 55°-70° C., inclusive, 
and has been found to be about 11 for a temperature interval of 
10°. This is of the order of magnitude demanded by the law of 
Van’t Horr and Arruentus for the temperature coefficient of a 
chemical reaction, but is much less than the temperature coeffi- 
cient of duration of life of sea urchin eggs as determined by LOEB. 
I wish to acknowledge my indebtedness to Professor W. A. 
SETCHELL for his many helpful suggestions and criticisms, and 
to A. R. Moorr, whose continued interest and assistance have 
made this paper possible. 
UNIVERSITY OF CALIFORNIA 
BERKELEY, CALIFORNIA 
