206 BOTANICAL GAZETTE [APRIL 
violet. The inner cells are still basic. This shows that the acid 
had penetrated a little way. The inner cells develop acidity much 
more rapidly than in the control. 
Of seeds treated as above with N/7o butyric acid, and after- 
ripened at 5° C. with testas on, 52 per cent germinated in 53 days; 
the others decayed. The testas were removed from a lot of seeds 
after soaking in N/7o butyric acid, and the naked embryos kept on 
moist cotton at 5° C.; these germinated in 16 days. As shown 
by the large number of seeds which were killed, N/70 butyric is too 
strong. More dilute solutions are being used now. 
N/800 butyric has about the conductivity of N/rooo acetic 
and N/3400 HCl, which were found to be effective; therefore 
that is being tested as well as still more dilute solutions. The more 
dilute solutions are not toxic, instead they greatly increase the rate 
of the process of after-ripening; therefore, germination is hastened. 
The after-ripening period of seeds with testas intact was shortened 
from 80-90 days to 45-53 days; with testas removed, from 30 
days to 16-18 days. 
Summary 
Condition of the embryo in dry storage-—Food is stored in the 
_embryo i in the form of fatty oil; there is also considerable lecithin; 
\ neither starch nor sugar is present. The reaction of the cotyledons 
is acid, but the hypocotyl is slightly basic. The water-absorbing 
power of the hypocotyl is less than 25 per cent of the wet weight. 
There is a series of metabolic changes in the embryo during the 
_ period of after-ripening. The initial change seems to be an in- 
creased acidity. Correlated with this is an increased water-holding 
power, and an increase in the activity of catalase and peroxidase. 
Near the end of the period of after-ripening there is a sudden 
increase in the acidity, and in the water content; here oxidase 
first appears. All of these increase until the hypocotyl is 3-5 cm. 
long. At this time the fats decrease and sugar appears. Hydro- 
cyanic acid is present in the cotyledons. 
The after-ripening period can be greatly shortened by treating 
the embryos with dilute acids, HCI, butyric, and acetic. The water- 
holding power, the acidity, and the amount of peroxidase increase 
much more rapidly, and oxidase appears much earlier, than in 
untreated embryos. 
