§2 BOTANICAL GAZETTE [JANUARY 
Many such experiments indicate that the vigor and resistance of 
the seed to fungi increased greatly during the after-ripening process. 
These results prove that the juniper seed has a dormant embryo 
that goes through certain definite and well defined fundamental 
chemical and physical changes before germination can occur. 
Some changes occur also in the endosperm. 
© SHORTENING AFTER-RIPENING PERIOD AT 5° C.—The after- 
ripening period was shortened considerably by the constant 
‘temperature of 5° C., as has been shown, but attempts to shorten 
further this after-ripening period at 5° C. seemed to meet with 
difficulties. Guppy’s (15) method of forcing seeds to germinate 
by placing the soft pre-resting seeds (caught before going into the 
| rest period) at 20° C. was tested. None of these seeds germinated, 
| and it is evident that the juniper seed must pass through a more 
‘or_less_definite_rest_and_after-ripening period.’ This period was 
not shortened by the removal of the seed coats. EcKERSON (10) 
states that dilute acids greatly shorten the after-ripening period of 
the hawthorn. Dilutions of HC] between N/1oo and N/3200 had 
no effect upon the juniper seed. Neither sugar,enzyme, nor vitamine 
solutions shortened this period. Hydrogen peroxide gave no results. 
In the treatment with different percentages of oxygen, it was found 
that the catalase activity increased slightly with increased oxygen 
pressure, and that the germination was retarded two months. 
Seeds were treated with different percentages of ether ranging 
from 0.002 to 6.000. As long as these seeds were under the 
influence of ether they showed a decrease in catalase activity pro- 
portional to the percentage of ether used. After atmospheric 
conditions were restored, all seeds recovered their catalase activity, 
but the after-ripening period was lengthened from 1 to 3 months 
depending on the low and higher percentages of ether. If the ether 
acted by decreasing the permeability, then it was evidently reversible, 
contrary to the work of OstErHouT (27). It is more probable, 
however, that the ether acted as a narcotic agent. This is also 
shown by the behavior of the seed. Carbon dioxide was used in 
concentrations ranging from 0.5 to 100 per cent with a six day 
exposure. The higher percentages increased the catalase activity 
and shortened slightly the after-ripening period. The action here 
