1914] 



DA RSI E, ELLIOTT &• P EI RCE— GERMINATING POWER 



107 



germination 



of vigor. The following experiments furnished the grounds for this 

 statement. 



Experiment I. — Barley from the University of Wisconsin; 15 

 grams of the crop of 1905 and a like amount from the crop of 191 1, 

 washed with a saturated solution of copper sulphate. Experiment 

 set up March 8, 191 2. The data are in table I. 



On the eighth day the flasks were opened and emptied. No 

 infection was visible and both lots of seed had germinated freely. 

 It is to be noted, however, that the radicles from the 191 1 seed were 

 two or three times as long as those from the 1905 seed. The accom- 

 panying graph (fig. 1), constructed from the thermometer readings 

 of table I, indicates the evolution of heat in these two sets of seeds. 



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 1911 









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120 



150 



180 



Fig. i. — Barley (experiment I): 15 grams; broken line, 1905; solid line, 191 1 



Experiment II. — Barley from the University of Wisconsin and 

 from Ames, Iowa; 10 grams of each year. On account of the hulls, 

 no sterilization was attempted. Experiment set up as indicated in 

 1913- The data are in tables II and III. 



The fact that the 1909 seeds were very moldy when taken from 

 the flask accounts for the high temperature in that flask. Two 

 other experiments were set up at the same time, but as we were not 

 able to sterilize, the seeds were found to be covered with mold and 

 the unusually high temperatures were not thought worth recording. 



It is not of course to be expected that such seeds will show a 

 perfectly regular decrease in heat yield with increasing age. There 

 are too many other factors which may influence their viability. In 

 order correctly t< interpret the variations from this regular decrease, 



