HIS THEORY OF HEREDITY 109 



selected seven such pairs of characteristics and 

 observed the way in which they were distributed 

 in cases of hybridization. A concrete example will 

 make the matter clearer than abstract description, 

 and we will select one which has been brought 

 forward by Bateson,* and which is of easy com- 

 prehension by all. There are both tall and dwarf, 

 or " Cupid," sweet peas, these two kinds thus 

 affording, in this particular, a very striking and 

 easily-disinguished difference. Suppose now that 

 we cross the tall with the dwarf variety, secure the 

 resulting seeds and sow them, what results ? All 

 the plants which grow up belong to the tall variety. 

 It might be supposed that the tall variety had 

 simply wiped out the dwarf strain, but a further 

 experiment shows that this is not the case. Let 

 the tall children of the mixed tall and dwarf par- 

 ents be self-fertilized ; let the seeds thus obtained 

 be sown, and it will be found that the resulting 

 plants are mixed in character, and mixed, too, in 

 definite proportions. For it will be found that on 

 the average there are three tall specimens for 

 every one of a dwarf nature. It would appear then 

 that the dwarfishness was only hidden in the 

 children ; that its absence was apparent and not 

 real, and that the potentiality was there in the 

 germ and made itself evident in the grand-children. 

 To the character which alone appears in the first 

 cross is given the name " dominant " ; to that 

 which, existent in one of the original parents, 

 hidden in the children, becomes again obvious in 

 some of the grand-children, is given the name 



* " Mendelian Heredity," British Medical Journal, July 14, 1906. 



