302 



The Journal of Heredity 



vigorous stock in most cases. Her chil- 

 dren naturally inherited her vigor, 

 and it meant longevity for them. There 

 may have been some disadvantage aris- 

 ing from the large number of offsjiring, 

 but whatever it was, it was counter- 

 balanced by the very great advantage 

 which comes from the inheritance of 

 vigor, vitality, and a resistant consti- 

 tution. 



INFANT MORTALITY 



The higher infant mortality in families 

 of more than ten children reflects the 

 only disadvantage which Dr. Bell's 

 study shows to inhere in large families. 

 The fact that the surviving members of 

 these big families have extraordinary 

 longevity indicates that one's constitu- 

 tion is not permanently impaired by hav- 

 ing a dozen brothers and sisters. The 

 high death rate in childhood may be 

 largely due to the fact that the mother 

 has more children than she can properh' 

 look after. If this be the correct ex- 

 planation, then it is evident that what- 

 ever disadvantage arises from having 

 even an extreme number of offspring, 

 is not of the kind that results in perma- 

 nent debility of these offspring. Con- 

 sidering only the factor of heredity, it 

 is evident that there is no danger of 

 racial deterioration from large families: 

 that the families can hardly be too 

 large, under normal conditions. The 

 weak children of a jjopulation come not 

 from large families, but from small 

 families. 



Of course this does not mean that a 

 small family necessarily connotes weak- 

 ness of its members. Nor is it intended 

 here to suggest that superior women 

 should bear ten children apiece. It is 

 only desired to point out that, in a nor- 

 mal stock, a child with nine brothers 

 and sisters has, on the average, much 

 more vitality and strength than a child 

 with only one, because it has, on the 

 average, a better heredity. 



If superior parents want a large 

 family, they ought not to be discouraged 

 by the widesjjread but false idea that 

 every child beyond the second or third is 



'On the handicapping of the first-born. University of London, Galton Lalioratory for 

 National Eugenics, Eugenics Lcrturc Series X. London, Dulau & Co., 1914. An extended 

 review was jjiven in tlie Joi'KNAI. ok Hkrkditv, vi, pp. .V?2-.S.^f). July, l^l.S. 



* Data for the Problem of Evolution in Man. On Fertility, Duration of Life, and ReiJroduc- 

 tive Selection. By A. O. Powys. Biometrika, iv, |)p. 2.^.i-2W), London, 1905. 



likely to Vx) progressively handicapped. 

 If any is handicapped, it is the first- 

 born,^ but the eflect here is not very 

 great. The really important factor in 

 determining a child's vitality is not the 

 number of lirothers and sisters who have 

 preceded him, but the kind of stock he 

 comes from. Large families in superior 

 stock will produce su])erior children; 

 large families in the slums are likely to 

 produce inferior children. In discourag- 

 ing the latter families, care should be 

 taken not to discourage the former. 



EFFECT ON THE MOTHER 



The foregoing discussion has been 

 limited to the effect on the offspring of 

 having a large number of brothers 

 and sisters, and it has been shown that 

 the alleged "progressive debility" is a 

 misunderstanding. Nothing has been 

 said about the alleged "progressive de- 

 cline in the mother's health." That 

 question is too large to be discussed here, 

 but it may be noted that in this case, too, 

 the results dei)end largely on the kind 

 of inheritance the mother has. Powys' 

 careful study^ of the admirable vital 

 statistics of New South Wales shows that 

 the longest-lived women are those who 

 have had from six to eight children. A 

 larger family than that apparently is 

 unfavorable to the mother's physique, 

 while a smaller family also goes with 

 diminished vitality. This of course 

 does not mean that a woman of deficient 

 vigor could prolong her life by bearing 

 seven children ; it merely means that the 

 women with the greatest inherent vigor 

 tend to bear about that number of 

 children, without stiffering any diminu- 

 tion in longevity. 



The size of a family must naturally be 

 determined by many considerations be- 

 sides eugenics. As far as etigenics alone 

 is concerned, relatively large families, in 

 the sujjerior part of the population, are 

 desirable from the j^oint of view of the 

 parents and the children, as well as the 

 race. In eugenically inferior jxirts of the 

 ]M)i)ulation, the smaller the family the 

 ix'tter for all concerned. 



