700 THE AMEBIC AN NATURALIST [Vol. XLVII 



Hence these absolute differences must, for the sake of 

 convenience and of strict comparability, be reduced to 

 relative terms. The best way of doing this is to express 

 them in percentages of the general population values for 

 the same constant, where " general population" means 

 the whole mass of the particular strain and series of 

 seeds from which the seeds for the individual experi- 

 ments were drawn. 



In the discussion of the whole series of experiments 

 both absolute and relative values will be taken into account. 

 In the preparation of the diagrams for differences in 

 mean and S.D. the relative (percentage) values only will 

 be used. 



Table X gives the physical constants for the general 

 populations, and the numbers of seeds upon which they 

 are based. 



I now turn to the various comparisons. It would be 

 desirable to place before the reader the individual differ- 

 ences and their probable errors, but since these number 

 750 their publication is precluded by lack of space, and 

 the small summary tables must suffice. All these differ- 

 ences may, of course, be derived by the reader caring to 

 check the arithmetic from the tables of fundamental 

 constants. 



(To be concluded) 



