MENDELISM AND OTHER METHODS OI' DESCENT 225 



work in 1866 and their rediscovery by De Vries and Correns 

 in 1900. But in 1889 Galton published his book on *' Natural 

 Inheritance" including a chapter on eye-color in the human 

 species, in which the following statement occurs : 



'* Stature and Eye-colour are not only different as qualities, 

 but they are more contrasted in hereditary behaviour than per- 

 haps any other common qualities. Parents of different Statures 

 usually transmit a blended heritage to their children, but par- 

 ents of different Eye-colours usually transmit an alternative 

 heritage.'' ^ 



It is evident enough from the context that the author used 

 these words merely to describe the facts which he had ascer- 

 tained regarding differences of eye-color among members of 

 the same families, and not with the intention of proposing a new 

 theory of the mechanism of descent. Nevertheless, it launched 

 an expression which could be converted readily, and even un- 

 consciously, into a theory of alternative transmission of charac- 

 ters, and thus undoubtedly did much to lend popularity to the 

 ''rediscovery of the Mendelian principles." Galton appears 

 to have had no intention of suggesting that the transmission of 

 one character inhibits the transmission of another character. 

 He predicated transmission only from the standpoint of the 

 parents, and as shown in the characters of the immediate off- 

 spring, and fully understood that these offspring would be able 

 to transmit characters which their own bodies did not express. 

 But the Mendelian theories have discarded such reservations 

 and distinctions, and have gone over bodily to the assumption 

 of alternative inheritance in the most complete sense of the 

 words. They predicate the existence of character-unit particles 

 and of germ-cells which receive and transmit particles repre- 

 senting only one of a pair of contrasted parental characters. 

 But no such method of inheritance has been' proven, and no 

 such assumptions are required, or even permitted, by the facts of 

 Mendelism. 



Inheritance has been used unconsciously in two different 

 senses, to cover and confuse two distinct phenomena, the 

 transmission of characters and the expression of characters. 



'Galton, Francis, 1S89. Natural Inheritance, pp. 13S-139. 



