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1917] GROVES— DURATION OF SEEDS 183 



would be possible were it not for the fact that the small coefficients 

 give life durations too long for convenience in experimentation at 

 temperatures not considerably above the maximum. 



The difference between plants and animals in the size of the 

 coefficients manifests itself in another way. In the investigations 

 with animals the temperatures used are largely below 45 C, while 

 with plants it is not uncommon to use temperatures above 70 C. 

 and obtain an easily measurable life duration. The maximum 

 temperature usable is determined also in part by other factors, such 

 as percentage of water present and the general attunement of the 

 particular plant to the temperature. The lower the percentage 

 of water in the seed, the higher the temperature that can be used 

 with it. It is probable also that in forms like Ulothrix and Hy- 

 drurus, having maxima below 24 C. (27), the possible experimental 

 temperatures would not run so high. 



Discussion 



The rather close agreement between calculated and- found 



time-temperature formula for the coagu 



lation of protein can be applied as a temperature-life duration 



formula 

 ments. 



accumulation 



I make it possible to find some other equation which expresses more 



J adequately the relationship between the variables involved. In 



the experiments on wheat of 9 and 1 2 per cent moisture the average 

 deviation of the observed from the calculated temperatures is 

 less than 1 per cent. The corresponding average deviation for 

 the 17.5 per cent moisture content is about 8 per cent. The 

 unexpectedly large error with the 17.5 per cent moisture content 

 is due to the previously noted fact that a considerable part of the 

 time of exposure is consumed in heating the seeds up to the tempera- 

 ture of the bath. The uniformly increasing deviation of the 

 observed temperatures with short periods of time shows that 

 greater accuracy is possible with long time exposures. 



While in many reactions there is a consistent decrease in the 

 value of the coefficient Q I0 as the temperature increases, we do not 

 find such a trend here. Compared with animal tissue, the value of 



