364 Menders Experiments 



fertilisation, since sixteen individuals are included in the 

 series. Therefore the participators in the fertilisation are 



Pollen cells AB -V AB -V AB ^ AB -V Ab-\- Ab^ Ab^ Ab^ 

 aB + aB + aB + aB -h ab -\- ab -{- ab -{- ab. 



Egg cells AB^AB^AB-^AB^Ab^Ab^Ab^Ab^ 

 aB + aB + aB + aB ■\- ab -\- ab ■\- ab ■\- ab. 



In the process of fertilisation each pollen form unites on an 

 average equally often with each ^g^ cell form, so that each 

 of the four pollen cells AB unites once with one of the 

 forms of ^^g cell AB, Ab, aB, ab. In precisely the same 

 way the rest of the pollen cells of the forms Ab, aB, ab 

 unite with all the other ^^^ cells. We obtain therefore 



AB AB AB AB Ab Ab Ab Ab 

 'AB^ Ab '^ aB'^ ~^^ AB"^ Ab^ aB'^ ab^ 



aB aB aB aB ab ab ab ab 

 + -:r7 + -Ti + — r + -^rr. + -^; + -^ + 



AB ' Ab aB ' ab ' AB ' Ab aB ab' 

 or 



AB + ABb + AaB + AaBb + ABb +Ab-\- AaBb + Aab + 

 AaB + AaBb -\-aB + aBb + AaBb + Aab + aBb -\-ab=^ AB + 

 Ab-\-aB + ab + 2 ABb + 2aBb + 2 AaB + 2 Aab + ^AaBb^, 



In precisely similar fashion is the developmental series 

 of hybrids exhibited when three kinds of differentiating 

 characters are conjoined in them. The hybrids form eight 

 various kinds of ^gg and pollen cells — ABC, ABc, AbC, 

 Abe, aBC, aBc, abC, abc — and each pollen form unites 

 itself again on the average once w^ith each form of ^gg cell. 



The law of combination of different characters which 

 governs the development of the hybrids finds therefore its 

 foundation and explanation in the principle enunciated, 

 that the hybrids produce ^gg cells and pollen cells which 

 in equal numbers represent all constant forms which result 

 from the combinations of the characters brought together 

 in fertilisation. 



* [In the original the sign of equaUty (=) is here represented by +, 

 evidently a misprint.] 



