CHANGES ACCOMPANYING BREAKING OF REST PERIOD 41 



The heating prevented any color changes. The addition of 

 toluene had a similar effect. Where no special treatments were 

 given, the changes were quite marked, more so than the table indi- 

 cates. The extract from the etherized material which had been the 

 darkest colored in the beginning was the lightest after five days. 

 The changes were apparently due to bacteria. 



7. Gas Formation on Twigs. On February 27, 1914, some 

 one-year-old Red June apple twigs were collected. Similar lots were 

 immersed in pure water, and in 5, 10, and 20 per cent alcohol respec- 

 tively. After fifteen hours the following observations were made: 

 "The twigs in 5 per cent alcohol are entirely covered with small 

 gas bubbles; the material in 10 per cent alcohol and that in pure 

 water has fewer bubbles ; that in the 20 per cent alcohol has only a 

 very few, scattered here and there." Similar results were obtained 

 at various times. 



8. Gas on Finely Ground Cortex Preparation. Jonathan apple 

 twigs were collected on December 3, 1913. Some were immersed in 

 10 per cent alcohol for fifteen hours, some were bathed in water dur- 

 ing the same period. After two days the material was prepared for 

 the diastatic enzyme test as previously described. The preparation 

 from material which had been treated with alcohol became covered 

 with foam after twelve hours; none appeared on the preparation 

 from material which had been immersed in cold water. 



9. Effect of Etherizing Frozen Seeds. During 1912-13, Wig- 

 gans 1 carried on some studies concerning the rest period of seeds. 

 In one experiment he determined the effect of freezing and etheriza- 

 tion of seeds which had been previously soaked in water for three 

 hours. After treatment, the seeds were germinated between moist 

 filters. At least 100 seeds were used in each case. The freezing 

 temperature was a few degrees below C. Etherization was carried 

 out immediately after freezing. A somewhat weaker dose of ether 

 was applied than in the experiments described in this paper. The 

 results obtained in the germination tests are summarized in Table 14. 



It is seen that the freezing of soaked seeds reduced the percent- 

 age of germination in all cases below that of seeds which were soaked 

 but not frozen. But if the freezing was followed immediately by 

 etherization, the reduction in the percentage of germination was not 

 so marked. In other words, the ether treatment apparently hin- 



1. Wiggans, C. C. Studies Regarding the Rest Period of Seeds. Thesis. 

 University of Missouri, 1913. 



