o 22 



THE AMEBIC AX XATVRATJsT 



[Vol. XLVI 



throughout the experiment by approximately the same 

 number of individuals, we shall not only be sure that like 

 hereditary tendencies went into all branches of the ex- 

 periment at the beginning, but can feel confident that no 

 material source of error is introduced by a change in the 

 mean hereditary tendencies in either branch of the ex- 

 periment through the selective elimination (by reason of 

 relative unfitness for the chosen habitats) of certain (dif- 

 ferentiated) lines. 



These are ideal conditions, quite unattainable among 

 the innumerable difficulties of practical experimentation. 

 Omitting all particulars, I believe we may with reason- 

 able security consider the seeds which went into the orig- 

 inal starvation and into the original feeding series ran- 

 dom samples from the same individual plants. These 

 lines were maintained with moderate success throughout 

 the experiment. 



The following details concerning the methods of ma- 

 nipulating the material may not be irrelevant. 



Every seed was, so far as could be determined by in- 

 spection, perfectly formed and developed. 5 No seeds in 

 which the coats were sensibly wrinkled were included, 

 since this might indicate either a premature drying of the 

 seed in the pod, or a subsequent wetting. 6 



In harvesting, the plants were left in the field as long 

 as possible to allow the pods to ripen. They were then 

 gathered, and wrapped intact in newspaper to permit any 

 possible translocation of remaining plastic materials 

 from the stems or the pod walls to the seeds. 7 



preclude the possibility of a seed containing a weevil which had not emerged 

 up to the time of planting. A large proportion of the seeds planted in these 

 experiments was also weighed individually for use in pure line and other 

 investigations. Of course the seeds giving rise to the plants with which 

 the experiments originated— the NH, ND, US, FS and BG individuals- 

 are of this wrinkling. * PenmentS t0 determme what the real C 



1 This precaution applies to onlv two of the original series, to NH and 

 ND, but not to FS, US and BG. 



