MENDEL'S EXPERIMENTS 9 



This is shown in the following diagram in which the 

 impossible combinations are omitted because, otherwise, 

 the diagram would be overcrowded. 



> I I 



i i ■ 



, - — 



■ ~" 1 1 



■ ■ r 



Round. Wrinkled. Yellow. Green. Coloured. Wliite. 



Having described so much of his experimental work 

 in detail, Mendel proceeds : " Still further experiments 

 were made with a smaller number of plants in which the 

 remaining characters (shape of pod, length of stem, and 

 so on) were united into two-pair and three-pair hybrids ; 

 and all with similar results. There can be no doubt, 

 therefore, as regards the whole of the characters con- 

 cerned in the experiments, that it is valid to say that 

 the progeny of the hybrids in which several essentially 

 different characters are combined are ranged in a series 

 which is developed by combining the ratios for each 

 pair of characters.* Thus it is shown at the same time 

 that the behaviour of every two differentiating charac- 

 ters is independent of the remaining differences in the 

 original parents." 



The purport of this statement is, as regards Mendel's 

 seven pairs of characters whose ratios in the hybrids' 

 progeny are in every case 3:1, that the progeny of 

 hybrids whose parents differed in two of these pairs are 

 ranged in a series developed by combining the separate 



* Stellen sic Glieder einer Combinationsreihe vor, in welchem die 

 Entwicklungsreihen fiir je zwei differirende Merkmale verbunden 

 sind. 



