234 



The Journal of Heredity 



ters. No one will suppose that life 

 partners "infect" each other in these 

 respects. Certainly no one will claim 

 that a man deliberately selects a wife 

 on the basis of a resemblance to himself 

 in these points; but he most certainly 

 does so unconsciously — a fact not dis- 

 covered until the application of exact 

 methods to the study of heredity 

 revealed it and destroyed the old popular 

 belief that unlike persons tend to marry 

 each other. Assortative mating is now 

 a well-established fact, and there is 

 reason to believe that much, if not 

 most, of the resemblance between hus- 

 band and wife as regards tuberculosis 

 is due to this fact, and not to infection. 

 The comparison between heredity and 

 environment which I made above is, 

 therefore, a perfectly legitimate one — 

 that is, .02 iDetween environment and 

 phthisis in the child, .50 between a 

 tuberculous parent and the same disease 

 in the child. 



We would not dogmatically assert 

 that right environment is of no im- 

 portance in the case of tuberculosis; 

 but our knowledge justifies us in assert- 

 ing that no feature of the environment 

 is as important as the heredity; and 

 that the effective way to stamp out the 

 White Plague is not to be found in the 

 multi]3lication of sanatoria and restric- 

 tive regulations, or even in the better 

 sanitation of our slums, desirable as 

 these things may be in themselves; but 

 that tuberculosis will be most surely 

 and quickly eradicated when marriages 

 between persons who come from tuber- 

 culous stocks are prevented. 



EMPLOYMENT OF MOTHERS 



Now take the question of employment 

 for mothers. There has been a deal of 

 agitation on the subject in recent years, 

 and a certain amount of legislation has 

 been passed, particularly in France, to 

 relieve mothers of work outside their 

 own homes. This is a desirable object 

 in many ways, but if it is claimed, as it 

 usually is claimed, that emijloyment of 

 mothers is detrimental to their children, 

 and that mothers who stay at home 

 and give all their time to their children 

 will V)nng up healthier and more 

 intelligent children, the assumi)tion is 



involved that the character of the child 

 is due to his environment as well as to 

 his heredity; and the eugenist properly 

 may demand the right to be heard. 

 It is possible to measure with fair 

 accuracy the correlation between em- 

 ployment of mother and various char- 

 acters such as weight, height, health and 

 intelligence of her children. This has 

 been done with some carefully compiled 

 Scotch statistics, and it has been found 

 that the correlations are almost insig- 

 nificant, averaging .11. To put the 

 conclusion in less mathematical langu- 

 age, the fact that a mother may be 

 employed outside her own home is 

 found not to have any noteworthy 

 unfavorable result on such characters 

 of the children as were measured — - 

 namely, height, weight, general health 

 and general intelligence. On the basis 

 of these figures, the eugenist demands 

 that the movement for changes in our 

 present social arrangements, .such as 

 will permit mothers to stay at home and 

 give all their time to their children, 

 appear in the proper light, and that it 

 do not claim to be able to improve the 

 character of the children, when that 

 character is really determined at birth 

 and can be little influenced afterward 

 by any except extraordinary environ- 

 mental conditions. 



These problems of bad breeding are 

 pressing problems, but I have discussed 

 them long enough. After all, eugenics, 

 as its name indicates, is more interested 

 in good breeding than in bad breeding. 

 Let us see how heredity and environ- 

 ment are related in the production of 

 great mental and moral sui^eriority. 

 If we can learn that, we ought to be in 

 the way of ]:)roducing more such super- 

 iority in the world — a thing as to the 

 desirability of which there need be no 

 argument. 



If success in life — the kind of success 

 that is due to great mental and moral 

 su])eriority — is due to the opportunities 

 a man has, then it ought to be pretty 

 evenly distril)uted among all the ])ersons 

 who have had favorable oi)])ortunities. 

 l)ro\-i(k(l we take a big enough number of 

 persons to allow the laws of ])r()bability 

 full ])lay. England offers a good field 

 to investigate this ]x:»int, becau.se Oxford 



