INCREASE IN THE WEIGHT OF THE ENTIRE BODY. 59 



surrounding conditions are here the sole factor deter- 

 mining the difference. The Indians of North America 

 living on the mountains are smaller than those living 

 on the plains, a correlation which may be associated 

 with the greater abundance of food on the plains. 1 But 

 under like conditions half-breeds tend to be taller than 

 their parents, and have a slightly different curve of growth, 2 

 here again indicating that much must be allowed to the 

 peculiarities of the species on which any set of external 

 conditions happens to be acting. Further, Boas has 

 found that first-born children are, in the end, taller and 

 heavier than others of the same family. 3 We are aware of 

 no conditions compatible with life in which the general 

 character of the growth curve with its acceleration 

 during adolescence can be altered. Minor varia- 

 tions may, however, arise. From a study of the 

 relations of the curves for the two sexes under varying 

 conditions, it appears (Roberts' Tables) that the environ- 

 ment has more influence on the male than on the female, 

 and that under the most favourable conditions the two 

 curves run more nearly parallel owing to the bettcr 

 growth of the males ; but the cause of this may be 

 sociological rather than strictly biological. 



The weight of the individual at any period of 

 development must be looked . upon as one factor 

 influencing further growth. Mohring found that the 

 loss of weight 4 occurring in infants during the first few 

 days of life was more marked in those whose weight at 

 birth was small. Bowditch, 5 and also Porter, 6 have 



1 Boas, Mem. of the Internal. Congress of Antliropologv, 

 Chicago, 1893. 



2 Boas, Pop. Sci. Montlily, 1894. 3 Boas, Science, March I, 1895. 

 A Mohring, Inaiig. Diss, Heidelberg, 1891. 



3 Bowditch, Growth of Children. Twenty-second Annual Report 

 of the State Board of Health of Massachusetts, Boston, 1891. 



6 Porter, Transaction Academy of Sciences, St. Louis, 1894. 



