THE LATEST STAGE 247 



These relations are explained simply if we suppose 

 that the germ cells of the original plants bear " tall- 

 ness " or " dwarf ness " as one pair of contrasted 

 characters. When a tall plant is crossed with a dwarf 

 one, all the hybrids, though externally similar to the 

 dominant parent, have germ cells half of which bear 

 " tallness " and the other half " dwarf ness " in their 

 potential characters. Each germ cell bears one or 

 other quality, but not both. Thus when, by the chance 

 conjunction of a male with a female cell from these 

 hybrids, a new individual is formed, it is an even chance 

 whether, as regards the qualities of tallness and dwarf- 

 ness, we get two like or two unlike cells to meet ; 

 and, if the cells be like, it is again an even chance 

 whether they prove both " tall " or both " dwarf." 

 Hence, in the next generation, we get one quarter 

 pure " tails," one quarter pure " dwarfs," while the 

 remaining half are hybrids, which, since tallness is 

 dominant, resemble the pure " tails," and in appear- 

 ance give three-quarters of the seedlings that character. 

 It will be seen that the methods of inheritance are 

 different in the cases of dominant and recessive 

 characters. While an individual can only transmit 

 a dominant character to his descendants if he himself 

 shows it, a recessive character may appear at any time 

 in a pedigree if two individuals mate who carry the 

 recessive character concealed in their germ cells, 

 though not outwardly visible in themselves. But in 

 the majority of cases the conditions of inheritance are 

 far more complicated than would appear from the 

 study of two simply contrasted qualities in the green 

 eating pea. For instance, qualities may act as 

 dominants or recessives according to sex or other con- 



