PLANT HYBRIDIZATION BEFORE MENDEL 109 



One of the most striking features of Laxton's paper is the fol- 

 lowing remarkable, detailed observation, distinctly Mendelian in 

 character, and one which should entitle the paper to especial in- 

 terest. 



He says : 



"l have also noticed that a cross between a round white and a blue 

 wrinkled pea, will in the third and fourth generations (second and 

 third year's produce) at times bring forth blue round, blue wrinkled, 

 white round, and white wrinkled peas in the same pod, that the white 

 round seeds when again sown, will produce only white round seeds, that 

 the white wrinkled seeds will, up to the fourth or fifth generation, pro- 

 duce both blue and white wrinkled and round peas, that the blue round 

 peas will produce blue wrinkled and round peas, but that the blue 

 wrinkled peas will bear only blue wrinkled seeds." (p. 13.) 



There does not exist anywhere, in the pre-Mendelian literature, 

 any other similar, clear, distinct, or detailed statement of an ob- 

 servation of segregation involving two pairs of characters. So far 

 as it has come to the knowledge of the writer, there exists no 

 similar observation, or one of equal value, or so closely approxi- 

 mating an analytical statement, preceding Mendel's account. 



It is interesting to trace, in Laxton's conclusions from the 

 above, the manner in which the logic of the situation appealed to 

 his mind. 



"This would seem to indicate," he says, "that the white round 

 and the blue wrinkled peas, are distinct varieties derived from 

 ancestors respectively possessing only one of these marked quali- 

 ties." (p. 13.) 



This in itself is a genetic conclusion. In Mendel's case, such 

 a fact pointed to the purity of the gametes. To Laxton's mind, 

 it indicated a pure line of similar ancestors — the same thing in 

 principle, but less analytically stated. Laxton is interested more 

 in the ancestors than in the manner of transmission ; Mendel in 

 the mechanism of the transmission itself. Thus Laxton says: 



"In my opinion the white round peas trace their origin to a dwarfish 

 pea having white flowers and round white seeds, and the blue wrinkled 

 varieties to a tall variety having also white flowers, but blue wrinkled 

 seeds." (p. 13.) 



One of the principal objectives of the early breeders was to 

 ascertain when and how a "variety" could be "fixed." Laxton con- 

 cludes that three or four years is 



", . . the shortest time which I have ascertained it takes to attain the 



