EX HA US TIVENESS. 7 3 



was never trusted. Many plants were measured 

 while young, when nearly full grown, and when 

 matured. Equal numbers of the two kinds 

 were cut down and weighed. Records were 

 kept of the rate of germination, of the periods 

 of flowering, and of productiveness both as to 

 the number of capsules produced and as to the 

 average number of contained seeds. Finally, 

 the tables of measurements were submitted to 

 Francis Galton in order to insure against error 

 and to have them examined by the best statis- 

 tical methods. Darwin intended at first to 

 raise only one generation of crossed and self- 

 fertilized seedlings of each kind, but in many 

 cases he went as high as ten generations. 

 Plants of different generations were exposed to 

 different conditions in successive years. He 

 started crossed seeds of Ipomcea purpurea (third 

 generation) forty-eight hours later than the 

 self-fertilized; seeds were sown outdoors late 

 in the season, and only one stick given to each 

 set to climb on ; two lots were sown in a shady 

 and weedy part of the garden ; two other lots 

 were sown in a bed of candytuft; seeds from 

 the same plant were sown, the crossed in one 

 corner and the self-fertilized in another corner 

 of a tub in which a Brugmannia had been grow- 

 ing, and in which the soil was excessively 



