MENDEL'S DISCOVERY xxxiii 



then proved by breeding further generations (i) that these 

 green peas contain the character in a pure state and yield 

 no other colour ; (2) that one third of the yellow peas 

 are similarly pure ; (3) that the remainder or half the 

 generation are heterozygotes, which when interbred 

 behave in precisely the same manner as the second 

 generation exclusively composed of heterozygotes. Con- 

 tinuing the process to infinity the yellows and greens 

 would sort themselves out into two equal bodies of pure 

 yellow and pure green respectively. 



I should be the last to undervalue these results, but 

 their true worth is not enhanced by such astonishing 

 exaggeration as that which appears in the passage I have 

 quoted from R. H. Lock on p. xxvii. The human mind 

 is so constituted that a touch of megalomania is to be 

 expected, is even to be regarded with sympathy, in the 

 first flush of a new victory over the unknown ; and I have 

 always felt that the revelation of ' the underworld of 

 gametes ' ] by Mendel's discovery is a fascinating and 

 arresting addition to knowledge. But to suppose that 

 the problem of Evolution is thereby solved, or likely to 

 be solved, is unreasonable. Lock's statement not only 

 reveals a grotesque exaggeration of the importance of 

 the results achieved, but also conveys the impression 

 that the Mendelian is to some extent paralysed by the 

 contemplation of his own work. He seems to say, — 

 ' We have solved the mystery so far as it can be solved, 

 and all that is now expected of us is to apply and apply 

 again the Mendelian principle to one strain after another.' 

 Such an outlook does not offer much hope of progress 

 in solving the problem of Evolution. 



' How have living things become what they are, and 

 what are the laws which govern their forms?' These 

 1 Bateson, Report British Association, 1904, p. 583. 



POULTON 



