HEREDITY 499 



dispersal, the point binomial." In illustration of characters 

 that exhibit Mendelian inheritance, the following may be 

 cited, the dominant condition which prevails over its alter- 

 native in the first cross-bred generation being named first 

 in each case: Hornlessness and the presence of horns in 

 cattle, normal hair and long ' Angora ' hair in rabbits and 

 guinea-pigs, kinky hair and straight hair in man, crest and 

 no crest in poultry, extra toes in poultry and the normal 

 number four, bandless shell in wood-snail and banded shell ; 

 yellow cotyledons in peas and green ones, round seeds in 

 peas and the wrinkled form, absence of awn in wheat and 

 its presence, susceptibility to rust in wheat and immunity 

 to this disease, two-rowed ears of barley and six-rowed ears, 

 markedly dentate margin in nettle leaves and slightly toothed 

 margin. Why one character should be dominant and its 

 alternative recessive we do not know. It is often supposed 

 that a dominant character implies something plus, the pres- 

 ence of a definite * factor ' ; while the corresponding reces- 

 sive character implies the absence of that * factor '. But it 

 is difficult to hold to this consistently. 



The modern study of heredity suggests that our personal- 

 ity is made up of many strands which go back into antiquity 

 and which have a unique combination for each individual. 

 The strands are ancient, but the individual, as Jennings 

 (1911) says, " is a new knot ". And it seems an important 

 fact that a good deal is known in regard to " the intimate 

 material processes of the interweaving ". There is a fresh 

 unification at the beginning of each individual life, a fresh 

 unification that implies some measure of unpredictability and 

 freedom from the past. 



The strands of each individual knot diverge before and 

 behind us. " Those in my knot have come from a hundred 



