1914] 



DA RSI E, ELLIOTT &• PEIRCE— GERMINATING POWER 



ill 



For the sake of comparison, the accompanying curves are given 

 (figs. 2, 3), but attention should be called again to the fact that, 

 owing to the hulls, no attempt at sterilization was considered worth 

 while, and hence there was very considerable molding in the Dewar 

 flasks, with a corresponding rise in temperature independent of the 

 heat yielded by the germinating barley. That this is the case will 

 be more plainly shown in subsequent experiments and figures. 



In spite of the various defects in this experiment, it is clear not 

 only that the germinating power of seeds declines from year to 

 year, but that this is indicated and can be tested by ascertaining 

 the heat yield in such a good insulator as silvered Dewar flasks. 

 Furthermore, inspection of the tables will show not only that the 

 youngest seeds show the highest percentage of germination and the 

 greatest heat yield, but they respond most quickly to the influence 

 of conditions favorable to germination. They reach the maximum 

 percentage of germination and maximum temperature sooner than 

 older seed. 



Experiment III. — Red clover (Trifolium pratense); 25 grams 

 of seed from the crop of 1904 and the same amount from 191 1; 

 sterilized by washing with a concentrated aqueous solution of corro- 

 sive sublimate which was removed by repeated rinsings with boiled 

 distilled water; placed in two sterile flasks and covered with boiled 

 distilled water previously reduced to room temperature. At the end 

 of 18 hours the water was poured off and the plugs carefully replaced 

 in the necks of the flasks. The experiment w r as set up on February 

 2o 7 191 2. The temperature record is given in table V. 



TABLE V 



Date 



February 20 



21 

 21 

 22 

 22 



23 



23 

 24 



24 



25 



25 



4 



9 



4 

 10 



5 

 9 

 5 

 9 

 5 

 9 



00 

 30 



30 

 00 



30 



30 

 30 



30 

 30 



3:00 



P.M. 

 A.M. 

 P.M. 

 A.M. 

 P.M. 



A.M. 



P.M. 

 A.M. 

 P.M. 

 A.M. 



P.M. 



Hours 

 elapsed 



Room 



Max. 



1 



Min. 



1004 



■ - m ^h 



i7?6C 

 17.8 







i8?2oC. 



• »-»»* 



175 



245 

 42.0 



49 5 

 66.5 



74 5 



9i 5 



99 5 

 116. 



122.0 



i7?i6C. 



l6?39 C. 



18.10 

 17.90 

 17.80 

 17.70 



17.70 

 17.70 



18.00 



18.40 



17.6 



17.05 



16.50 



17.7 

 18.0 



17.6 



17-7 



17.7 



17.7 



17.16 



16.39 



17. ii 



16.50 



17.16 



16.50 



24.70 



25.80 



^ m ^^ ^» m ^^W 







IOII 



i8?ioC. 

 18,20 

 18.60 

 20.20 



21 70 



24-50 

 2540 

 26.30 



26.45 

 27.40 

 27.50 



