402 BOTANICAL GAZETTE [may 
calling attention to the fact of the combined participation of the 
embryo and endosperm in the data below. 
From a large number of determinations the following will give 
an idea of the results. Each curve represents the average of the 
rates derived from both chambers for the periods tested. In 
0 fig. 8, curves are shown 
dj 
indicating the absorp- 
tion rates for intact and 
: seared seeds. These 
‘ determinations were 
y made during December 
ue and early January, 
a 4 = . > 
| mag when the germination 
~-.9 
was averaging about 60 
per cent for intact seeds. 
It is evident that the 
\ 
™ 
. . * > 
fe : absorption rate 1s raised 
noticeably by searing. 
In most of the curves, 
n6 
a steady tendency is 
noted for the rate of 
absorption to rise with 
the length of the period 
tested. In many cases 
the high absorption 
—_—_—_—" 
ue 10 Hours 30 noted beyond the 25-3° 
Fic. 9.—Rates of oxygen absorption for wild hour periods is asso- 
oats for December and early January in terms of ciated with the breaking 
+ CC. = . . 
c. per hour per gm. dry weight; rate for intact of the seed coats ™ 
seeds, solid line; for seeds tested in 93 per cent 
oxygen, broken line. germination. Earlier 
: increases in rate, how- 
shoes: must not be ascribed to this cause. If now for this same 
period comparison be made of the absorption rates in the air 
and in an atmosphere of 93 per cent oxygen, the difference between 
the two conditions is marked (fig. 9). Further tests in 79 per 
cent oxygen revealed rates midway between those found for air 
and for 93 per cent oxygen; while absorption in 7 per cent oxygen 
