80 Mendel's Experiments 



perceive a substantial agreement. Apart from the fact 

 that from the union of a white and a purple-red colouring 

 a whole series of colours results, from purple to pale violet 

 and white, the circumstance is a striking one that among 

 thirty-one flowering plants only one received the recessive 

 character of the white colour, while in Pisum this occurs 

 on the average in every fourth plant. 



Even these enigmatical results, however, might probably 

 be explained by the law governing Pisum if we might 

 assume that the colour of the flowers and seeds of Ph. 

 multiflorus is a combination of two or more entirely 

 independent colours, which individually act like any other 

 constant character in the plant. If the flower colour A 

 were a combination of the individual characters A 1 + A 2 + ... 

 which produce the total impression of a purple colouration, 

 then by fertilisation with the differentiating character, 

 white colour, a, there would be produced the hybrid unions 

 A l a + A 2 a + ... and so would it be with the corresponding 

 colouring of the seed-coats*. According to the above 

 assumption, each of these hybrid colour unions would be 

 independent, and would consequently develop quite inde- 

 pendently from the others. It is then easily seen that 

 from the combination of the separate developmental series 



* [It appears to me clear that this expression is incorrectly given, 

 and the argument regarding compound characters is consequently not 

 legitimately developed. The original compound character should be 

 represented as A 1 A 2 A S ... which when fertilised by a^ gives A^A^A z ...a 

 as the hybrid of the first generation. Mendel practically tells us 

 these were all alike, and there is nothing to suggest that they were 

 diverse. When on self-fertilisation, they break up, they will produce 

 the gametes he specifies ; but they may also produce A 1 A l and A 2 A 2 , 

 A 1 A 2 a, &c., thereby introducing terms of a nature different from any 

 indicated by him. That this point is one of the highest significance, 

 both practical and theoretical, is evident at once.] 



