52 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 HC1 between N/100 and N/3200 had 

 no effect upon the juniper seed. Neither Ibgar, 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.C02 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 



