12 HEREDITY AND SOCIAL FITNESS 



main physically sound and mentally able — that is, capable of under- 

 standing the nature and possibilities of his environment; he must show 

 some degree of aggressiveness and perseverance in his course of action, 

 and possess moral standards which bring his course of life into proper 

 relation with the efforts of others. In applying this test we have had 

 regard to the balance of all these factors, but because certain of these 

 essential traits, namely, calculating ability, aggressiveness, and per- 

 severance, were noticeably present or absent in the founders of the 

 various lines and their evaluation in relation to extraneous influences 

 less difficult than in the case of many other traits, especial attention 

 has been directed to them. In this way, two great networks have been 

 outlined, numbering, all told, 1,822 individuals. 



In surveying such an extensive network it is obviously out of the 

 question to balance accurately all the factors which go to the making 

 of the complex individual. But far from giving up such an under- 

 taking as futile, it has been found profitable to attempt to group these 

 individuals into classes with reference to these traits or types of re- 

 action. It is felt that in the absence of such objective measurements 

 as modern psychology is attempting to develop, a balancing of evidence 

 as to these reactions in a fairly uniform environment gives results which 

 are valuable for human genetics in its present state of development, 

 and may even point the way to the more critical methods of the future. 



