Chap. I. INTRODUCTORY REMARKS. 19 



Limnanthes. He also calculated the average height 

 of the crossed and self-fertilised plants in the seven 

 tables by a more correct method than that followed 

 by me, namely, by including the heights, as estimated 

 in accordance with statistical rules, of a few plants 

 which died before they were measured; whereas I 

 merely added up the heights of the survivors, and 

 divided the sum by their number. The difference in 

 our results is in one way highly satisfactory, for 

 the average heights of the self-fertilised plants, as 

 deduced by Mr. Galton, is less than mine in all the 

 cases excepting one, in which our averages are 

 the same ; and this shows that I have by no means 

 exaggerated the superiority of the crossed over the 

 self-fertilised plants. 



After the heights of the crossed and self-fertilised 

 plants had been taken, they were sometimes cut down 

 close to the ground, and an equal number of both 

 weighed. This method of comparison gives very 

 striking results, and I wish that it had been oftener 

 followed. Finally a record was often kept of any 

 marked difference in the rate of germination of the 

 crossed and self-fertilised seeds, of the relative periods 

 of flowering of the plants raised from them, and of 

 their productiveness, that is, of the number of seed- 

 capsules which they produced and of the average 

 number of seeds which each capsule contained. 



When I began my experiments I did not intend to 

 raise crossed and self-fertilised plants for more than a 

 single generation; but as soon as the plants of the 

 first generation were in flower I thought that I would 

 raise one more generation, and acted in the following 

 manner. Several flowers on one or more of the self- 

 fertilised plants were again self-fertilised ; and several 



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