VIRILE SENTIMENT 69 



action or of social education must be modified. 

 There is a pitfall lying across our path, and we 

 must be careful to see it, in order that we may avoid 

 the consequences of falling into it. 



Before I pass on to consider the other main purpose 

 of this paper, i.e., the question whether the evidence 

 justifies us in believing that the processes of segrega- 

 tion and gametic purity are operating in human 

 heredity, I would like to make the task a little easier 

 by tabulating all the possible types of mating which 

 can occur. We are assuming for the present that 

 human beings are composed of a number of alternative 

 or unit characters. These are disposed in pairs, 

 and each unit character in a pair is capable of re- 

 placing the alternative one in the processes of here- 

 dity. One of these unit characters we call dominant, 

 and the other recessive. This assumption being 

 tentatively accepted, we may classify human matings, 

 so far as particular pairs of characters are concerned, 

 in the following way, and from such matings offspring 

 of the nature indicated will be expected : — 



Parent : Parent. Nature and proportion of expected Offspring. 



RR X RR = AW RR. 



DD X RR = AW DR &nd all visibly D. 



DD X DR = I D D + l D R = SiW visibly D. 



DR X DR = lDD+2DR{vkih\yD)+lRR. 



DR X RR =-. 1 DR (visibly D) +1 R R. 



DD X DD = AW DD. 



Now we are in a position to consider what is, 

 next to the question of man's origin and destiny, 

 one of the most intensely interesting of human 

 questions : Do the alternative characters which 

 make up human beings, and which decide what we 



