20 A MANUAL OF MENDELISM 



were or were not pure in each of the two pairs of 

 characters. The result was as follows : 



Pure round Pure round Impure round Impure round 



and pure and impure and pure and impure 



yellow yellow yellow yellow 



25 19 22 21 



With the hybrid) 

 as pollen-bearer / 



With the pure» 



parent as pollen- [ 20 23 25 22 



bearer ) 



In Mendel's final experiment, the hybrids between 

 parents differing in one pair of characters were mated 

 with the hybrids between parents differing in another 

 pair. One hybrid was got by mating parents having 

 violet-red flowers and short stems with others having 

 white flowers and short stems, while the other was got 

 by mating parents having white flowers and long stems 

 with others having white flowers and short stems. If 

 Mendel's theory be true, then the materials offered by 

 the two kinds of hybrids, putting V = violet-red, 

 w = white, L = long, and s = short, should have 

 been : 



By one hybrid By the other 

 V w 



• W w. 



And this mating should have produced equal numbers 

 of the combinations Vw and ww on the one hand and 

 of Ls and ss on the otlier ; but, as the two pairs of 

 materials are distributed independently and simul- 

 taneously, there should have resulted equal numbers of 



