226 Castle 



continuously, or various blends between tbeni, while the gametes which 

 composed the heterozygotes may still be pure in respect of the parental 

 characters. The degree of blending in the heterozygote has nothing to 

 do with the purity of the gametes. 



It must be recognised that in, for example, the stature of a civilised 

 race of man, a typically continuous character, there must certainly be 

 on any hypothesis more than one pair of possible allelomorphs. There 

 may be many such pairs, but we have no certainty that the number of 

 such pairs and consequently of the different kinds of gametes is altogether 

 unlimited even in regard to stature. If there were even so few as, 

 say, four or five pairs of possible allelomorphs, the various homo- and 

 hetero-zygous combinations might, on seriation, give so near an approach 

 to a continuous curve, that the purity of the elements would be un- 

 suspected, and their detection practically impossible. Especially would 

 this" 1)6 the case in a character like stature, which is undoul)tedly very 

 sensitive to enräonmental accidents. 



It is, of course, quite possible that the gametes in such cases do 

 in fact vary as continuously as we see the zygotes do, but this cannot 

 yet be affirmed. The great theoretical significance of this question should 

 therefore lead us to suspend judgment for the present." 



The possibility here pointed out did not at the time impress me 

 as important, and I had well nigh lost sight of it until observations of 

 Nilsson-Ehle (1909), supported by those of East (1910) showed that 

 a Mendelizing color character may have double or even triple represen- 

 tation in the gametes of a plant. If a color character known to Mendelize 

 may have multiple representation in a gamete, the probability seemed 

 to me greatly strengthened that size characters are inherited as MendeUan 

 characters having multiple representation in the germ-cells. Lajstg (1910) 

 made an extended analysis of the case with special reference to our 

 observations on rabbits, applying in detail the general explanation which 

 Bateson had outlined in 1902 as a possible explanation of "blended" 

 inheritance. I see no reason to object to Lang's explanation as a 

 possibility. The work of Nilsson-Ehle had already led me to re- 

 cognize that possibility before the appearance of Lang's paper, and I 

 have expressly set it forth in some lectures published in 1911. Eut I 

 have not contented myself with recognizing the possible correctness 

 of the hypothesis;.! have been continuously engaged in investigations 

 designed to test its validity. Further work with size inheritance in 

 rabbits on a larger scale was carried out under my direction by Dr. 

 E. C. MacDowell, the results of which will shortly appear as a 



