MENDEL'S LIFE AND WORK 29 



every possible combination of simple character- 

 factors in equal numbers. In other words, the germ- 

 cells of the hybrids are never hybrid, but exactly 

 correspond to the original pure stocks, except that, 

 when tw^o or more pairs of characters are involved, 

 the character-factors are associated in every possible 

 way in equal numbers. ■•'" 



The reasoning by which Mendel arrived at the 

 foregoing generalisation may seem very simple and 

 natural to us now, but it was nevertheless a very 

 bold step in the fifties of last century to apply to 

 germ-cells, about wdiich scarcely anything was 

 known, facts which had been obtained by the 

 observation of pure and hybrid races. At the 

 present time it is very easy to believe that segrega- 

 tion of character-factors, each pair into two equal 

 groups, may take place ; in fact, most of the 

 phenomena of cell-division and the maturation of 

 the germ-cells lead us to suppose that such is 

 actually the case. 



C. Ix(]iDENTAL Results of Mendel's Work 

 ON Heredity. 



As in the case of all really important pieces of 

 work, the effect of Mendel's study of hybridisation 

 phenomena was by no means limited to the most 

 evident result. In the elucidation of questions 

 of heredity, Mendel's Law has of course been of 



♦Mendel's own words are that "Die Erbsenhybriden Keim-und 

 PoUenzellen bilden, welche ihre BeschattV.nheit nacli in <jleicher 

 Anzahl alien constanten Forinen entsprechen, welche aus der Com- 

 binirung der durch Befruchtung vereinigten Merkniale hervorgehen.'" 



