0. J. Bond 127 



and racial, and between varietal and specific characters would seem 

 to be a matter of integration of the gametic factors concerned in each 

 case, dominance and integration being closely associated. 



Thus the difference between the human mulatto hybrid and the 

 spotted negro hybrid and the pied animal hybrid is this. In the 

 mulatto the reduction of the volume of the colour factor is brought 

 about by a quantitative process of equal dilution over the whole skin 

 area, and not by a qualitative process of disintegration and segregation 

 of component factors for different skin areas as in the spotted negro or 

 the pied animal hybrid. 



By assuming the occurrence of a process of disintegration we extend 

 the principle of segregation into the constitution of gametic factors, we 

 assume intra as well as inter factorial segregation. 



If inter factorial segregation can explain the behaviour of unit 

 characters on Mendelian lines in the normal heterozygote, then intra 

 factorial segregation can explain the irregular behaviour of unit 

 characters in the abnormal heterozygote. 



If the foregoing conceiJtion of gametic architecture be at all true, 

 then it must stand the test of experience. 



The establishment of the Dutch pattern of coat colour in the rabbit 

 should show some evidence of the welding process by which two or 

 more less integrated unit characters (or rather the subordinate factors 

 which control them) have been integrated into one factor for Dutch 

 pattern. 



In the same way the resolution of the Dutch pattern into its 

 component unit characters should show, as it does in the case of the 

 Orkney rabbits (p. 112, Part I), the various steps in the disintegrative 

 process. 



The same process can be seen at work in the genesis of the hetero- 

 chromic pigeon. 



If true, this DISINTEGRATIVE THEORY should be applicable also to 

 the problem of the comparative sterility of inter-special and the com- 

 parative fertility of inter-varietal hybrids. 



Moreover it is quite independent of any pre-conceived notion as to 

 the ultimate nature of genetic factors. It is equally applicable to 

 the theory of gametic constitution which rests on an architectural or 

 mechanical as to one which rests on a chemical basis in the organisation 

 of the germ plasm. 



Since writing this paper my attention has been called to 

 H. H. Laughlin's(12) observations on the inheritance of colour in 



