48 
C. Experiment Station 
was recorded at the end of 7, 13 and 19 days and the radicles of all the 
seedlings which had germinated and remained healthy were measured at 
the end of seven days. From these measurements the average length of 
the seedlings in each lot was determined and recorded, and the measure¬ 
ments are arranged in groups on the basis of the length of the seedlings 
and recorded in the table in order to show the correlation which exists 
between the period of drying and the rate of germination. 
The percentage of germination of the lots treated for 12, 18, 24, and 36 
hours, was 62, 92, 96, and 96 respectively on the 19th day, and the average 
length of the radicles was 20.6, 46.7, 44.6, and 51.7 mm. respectively on the 
7th day. The correlation table shows that germination of lot 1 was not only 
greatly reduced in amount but also markedly diminished in rate, for the 
large groups of seedlings in this lot are to the left of the table and in the 
classes characterized by short radicles; while in lots 2, 3, and 4, the large 
groups are at the right side of the table and in classes characterized by 
long radicles. The facts of the reduced amount and retarded rate of germ¬ 
ination and the short average length of the seedlings in lot 1 point very 
definitely to the conclusion that when seeds are to be heated at 90° for 24 
hours, the 12-hour period of drying at 50° C. is too short. The 18-hour 
period is much better and the 24 and 36 hour periods are entirely 
satisfactory. 
Experiment 3, the results of which are also presented in table II, is 
like experiment 2 in every detail except that after preliminary drying at 
50° C. the seeds were heated at 95° C. for 8 hours. In this experiment, the 
germination of the 4 lots dried for 12, 18, 24 and 36 hours, was 38, 68, 90, and 
96 per cent respectively and the average length of the radicles of the 
seedlings increased with increase in length of the period of drying. In 
lots 1, 2, and 3, germination was both reduced in amount and retarded 
in rate and only in lot 4, which was dried for 36 hours, did germination 
occur without evidence of injury. It is evident from the results obtained 
from this experiment that when seeds are to be heated at 95° €. for as long as 
8 hours, the 12, 18 and 24-hour periods of drying at 50° C. do not give 
sufficient protection while the 36-hour period affords ample defense against 
the ordinarily injurious effects of the higher temperature. 
Since in experiments 1, 2, and 3 described above the protection given the 
seeds by the preliminary drying increased within limits with increase 
in both temperature and time of drying, it semed reasonable to assume that 
the increased protection is due primarily to the loss of water which occurs 
during the period of preliminary drying. In order to test this matter, 
certain experiments were made in which the amount of water lost was 
determined by weighing the seeds accurately at different stages in the 
course of the treatment. The water loss during the period of the prelimi¬ 
nary drying and during the time of heating at 95° C. was determined for 
each lot, and is given in Table III as percentage of the original air dry 
weight of the seeds. The total water content of a lot of seeds comparable 
in every way to the treated lots was determined by heating 100 seeds to 
constant weight at a temperature of 103-105° C., and this value is recorded 
in the table also as percentage of the air dry weight of the seeds. Using 
the values obtained for the water content of the air dry seeds and for the 
