Inconstancy of Improved Races 779 



found that it is highly variable and complies in 

 the main with Quetelet's law. Madia elegans, 

 a garden-species, has on the average 21 rays 

 on each head, fluctuating between 16 and 25 or 

 more. I saved the seeds of a plant with only 



17 rays on the terminal head, and got from 

 them a culture which averaged 19 rays, which 

 is the mean between 21 and 17. In this second 

 generation I observed the extremes to be 22 and 

 12, and selected a plant with 13 rays as the 

 parent for a continuation of the experiment. 

 The plants, which I got from its seeds, averaged 



18 and showed 22 and 13 as extremes. The total 

 progression of the average was thus, in two gen- 

 erations, from 21 to 18, and the total regression 

 from 13 to 18, and the proportion is thus seen 

 to diminish by the repetition rather than to in- 

 crease. 



This experiment, however, is of course too 

 imperfect upon which to found general conclu- 

 sions. It only proves the important fact that 

 the improved average of the second generation 

 is not the starting-point for the further im- 

 provement. But the second generation allows a 

 choice of an extreme, which diverges noticeably 

 more from the mean than any individual of the 

 first culture, and thereby gives a larger amount 

 of absolute progression, even if the proportion 

 between progression and regression remains 



