552 



SCIENCE. 



[N. S. Vol. VII. No. 173; 



to justify the view that the inheritance of 

 the cephalic index offers a most satisfactory 

 method of testing the laws of heredity. 



(2) Owing to the kindness of Mr. Francis 

 Galton, the Department of Applied Mathe- 

 matics in University College, London, was 

 placed in communication with Dr. Franz 

 Boas, of the American Museum of Natural 

 History, who is well known for his elaborate 

 system of measurements on North Amer- 

 ican Indians. With extreme kindness, Dr. 

 Boas* at once forwarded to England up- 

 wards of 1,000 sheets of measurements on 

 comparable Indian tribes. These tribes, 

 however, contain extremely mixed blood. 

 In the fewest cases were pure Indian an- 

 cestors noted ; one of the grandparents at 

 least exhibited, as a rule, European blood 

 —English, Dutch, French, Irish, etc. Dr. 

 Boas himself writes : 



" I could not give you any series that 

 was sufficiently extensive and embraced 

 pure Indians only, because among these 

 tribes the determination of i-elationships 

 offers peculiar difficulties. I am afraid that 

 your results may also bring out the loose- 

 ness of family relations. I should not be 

 surprised if the relation between father 

 and child were much lower than that be- 

 tween mother and child, because often 

 another person is actually the father of 

 the child." 



Dr. Bqas's last surmise is amply verified ; 

 it will be found from the table below that 

 the coefficient of heredity between father 

 and son is abnormally small, while that 

 between father and daughter is actually 

 less than the probable error of this series 

 of rneasurements ! If we put upon one side 

 any purely hypothetical supposition that 

 illegitimate births are more likely to be 

 female than male there would seem rea- 

 son to suppose some native custom by 



* It is diflBcult to sufficiently emphasize the disin- 

 terested service to science of men who do not ' mo- 

 nopolize ' their anthropometric measurements. 



which it is held less discreditable to pass- 

 off a daughter than a son upon the titular 

 husband. It may be asked whether, if the 

 racial mixture is so great and the paternity 

 so obscure, it was worth while to undertake 

 the lengthy arithmetic* required to deter- 

 mine the heredity correlations. The answer 

 is threefold : (a) if Galton's law of ancestral 

 heredity be correct, inheritance is not a ra- 

 cial character, but a general law of living 

 forms, and racial mixtures will not influence 

 the result ; (&) the results show that ob- 

 scure paternity does not prevent good values- 

 being found for other relationships ; in fact, 

 the fulfiluient of Dr. Boas's surmise is in 

 itself not without value, as showing how 

 well our algebraic theory fits itself to the 

 facts ; it might almost be said to provide a 

 scientific measure of the conjugal fidelity 

 of a race ; (c) it is always worth while to 

 undertake an investigation on the best ma- 

 terial available, even if it be poor material 

 for this purpose, for it emphasizes the need 

 of new and more elaborate observations. 



(3) It will be seen from the table that it 

 has only been possible to determine the 

 coefficient of heredity for small series, vary- 

 ing from 80 to 143 pairs of the seven rela- 

 tionships, four corresponding to the first 

 degree of direct kinship and three to the 

 first degree of collateral kinship. The 

 probable errors are, as might be expected 

 from such small series, large. Putting aside 

 the paternal relationship, we are justified in 

 drawing certain general conclusions, which 

 may be thus summed up : 



(a) The coefficients of heredity, as de- 

 determined from the cephalic index, differ 

 in all cases from those determined for 

 stature by less than their probable error 

 and, therefore, by less than the probable 

 error of their difference. The stature co- 

 efficients were obtained for the English 



* We have to thank Mr. Leslie Bramley Moore for 

 much aid in extracting the head measurements from, 

 the slips and calculating cephalic indices. 



