THE HEREDITY OF SEX 49 



character, who shall say what more or less of that 

 chromatin will produce ? 



In the case of my recessive pile, my interpretation 

 is that when the chromosomes corresponding to 

 two distinct characters such as colour and absence 

 of colour are formed they do not separate from 

 each other completely. Whether the mixture of 

 the chromosomes occurs in every resting stage of 

 the nucleus in the successive generations of the 

 gametocytes, or whether it occurs only in the 

 synapsis stage preceding reduction division, it is 

 not surprising that the colloid substance of the 

 chromosomes should form a more or less complete 

 intermixture, and that the two original chromosomes 

 should not be again separated in the pure condition 

 in which they came into contact. A part, greater 

 or less, of each may be left mixed with the other. 

 This is the probable explanation of the fact that 

 the recessive white plumage has some of the pigment 

 from the dominant form. Segregation, the repulsion 

 between chromosomes, or chromatin, from gametes 

 of different races may occur in different degrees 

 from complete segregation to complete mixture. 

 When the latter occurs there would be no segregation 

 and the heterozygote would breed true. The most 

 interesting fact is that a given factor in the cases I 

 have described, namely, colour of plumage and 

 pigmentation of skin in the Jungle fowl and the 

 Silky, is not a permanent and indivisible unit, 

 but is capable of subdivision in any proportion. 

 Bateson has already (in his Address to the Australian 

 Meeting of the British Association) expressed the 

 same conclusion. He states that although some 

 Mendelians have spoken of genetic factors as per- 



