CHAPTER VIII 



HEREDITY 1. 



i. General 



Having discussed phj-siology, fluctuation, and natural 

 crossing, we are now in a position to examine the 

 inheritance of characters in crosses between two strains 

 of cotton derived from separate reputed species.* 



The evidence to be adduced in the following pages is 

 frequently most infirm beyond the second generation. 

 Leaving out of account the inefficient conditions under which 

 this part of the work has been done (Figs. 52a and 526), 

 the chief responsibility for this uncertainty lies with the 

 difficulty of preparing self-fertilised seeds. When an Fa 

 of two hundred plants is to be studied, we desire to avoid 

 the use of nets (Fig. 51) owing to their disturbing 

 effect upon growth ; yet, if nets ate not employed, we 

 necessarily raise Fg families which are contaminated. 

 Therefore it is better to dispense with the nets, and to 

 rogue out the F3 vicinists ; very often, however, such 

 decisions as to vicinistic origin are based on the appearance 

 of abnormal characters which might very well be due in 

 reality to some rare gametic combination following self- 

 fertilisation ; we thus argue in a circle ; a plant shows an 

 unexpected characteristic, therefore it is a rogue. We 

 have endeavoured to reduce the probability of such un- 

 just decisions by a system of voting, whereby no plant 



* The coming economic application of Mendel's Law to cotton will at first 

 be made through crosses of much more nearly related forms, and hence of 

 far greater simplicity than those which the author has chiefly investigated. 



