1921] PACK—JUNIPERUS 45 
a series of fundamental changes before germination. Of the many 
points of attack that are suggested by these experiments two were 
chosen: (1) changes preparatory to germination, and (2) means 
of shortening the after-ripening period. 
Changes preparatory to germination 
/ These are the changes that occur in the seeds stored at 5c. 
/Wwhich prepare them for germination. As the embryo of the dry 
seed is morphologically complete, increases very little in size, and 
shows only the transformation of cell contents, these processes 
could be spoken of as “‘foregermination”; but as this term has 
not been used in this country these processes will be referred to as 
after-ripening. The first point studied was the imbibition of 
water. 
TABLE X 
SHOWING PERCENTAGE ABSORPTION OF WATER 
(SEEDS DRIED AT 105° C, FOR MOISTURE DETERMINATION) 
o 
2 . Weight after submergence for hours indicated Latics 
Material § = | Weight a 
ae Maximum 
a 2 4 8 16 | 24 | 72 | 96 | 120! 360 |imbibition 
Enti 
Chron ey Use cia 00] 2.0018] 2.16] 2.37] 2-40] 2.41| 2.42] 2.42/2.43 | 2.42] 2.39] 23.22 
Endosperm and embryo coats d 
net during imbibition... .. . 19| 0.290 0.37) 0.98)... 2. rae w | ones 28.04 
dosperm and embryo coat 
on during imbibition. .... . 19| 0.201 0.375 24.84 
Table X shows that the seeds decreased slightly in weight after 
a few days, even when submerged in water. In examining the 
tables given by Laxon for the water absorption of seeds of Pinus, 
it was noted that he incidentally obtained similar results. To 
follow this more closely, seeds with coats on were placed on moist 
filter paper at 5°C., and at times samples were selected, coats 
removed, and the percentage of water in the seed, exclusive of 
coat, determined. Table XI gives these results and the per- 
centage of water in the seedlings as well. It should be noted that 
the water content of the seed decreased gradually until germination, 
when there appeared a very marked increase up to the time of the 
developed seedling. This percentage of water seems to be related 
to the change in the water absorbing power of seed contents, and 
