HEREDITY 



215 



Distributions of the M and N Blood Types in Various Racial Groups 



(After VVeiner) 



Racial Group 



M 



N 



MN 



North American Whites 



Indians, U.S.A. 



Australian aborigines 



Ainu , 



Chinese , 



Danes 



Egyptians 



Eskimos 



Germans 



Negroes (New York) . . 

 Russians 



29-0% 

 60.0 

 3.0 

 17.8 



33-2 

 29.1 



28.3 



66.2 



30.2 



28.4 



32.2 



21.0% 



4-9 

 67.4 



31.94 

 18.2 

 21.4 

 23.1 

 2.9 

 19.7 

 21.0 

 21.2 



50.0% 



35-1 

 29.6 

 50.2 

 48.6 



49-5 

 48.6 

 31.0 

 50.1 

 49.6 

 46.6 



In recent years several other blood antigens have been discovered. All 

 of these appear to be inherited as simple dominants. Of especial interest 

 is the Rh antigen, which has recently been found to be of considerable im- 

 portance. If a developing embryo develops the Rh antigen, and the mother 

 lacks the antigen, she may develop the corresponding antibody. This may 

 diffuse through the placenta into the blood stream of the embryo, sometimes 

 with fatal results. In such an event the father must have been either homo- 

 zygous or heterozygous for the Rh factor. Approximately 85% of North 

 American whites possess the Rh antigen. Considerably higher percentages 

 are found among Indians, Chinese and American Negroes. 



Knowledge of the inheritance of the blood antigens is not only of value 

 in cases of disputed parentage, but has also thrown considerable light on 

 racial variations and origins. And there is every indication that in the 

 future blood will tell more and more. 



■>>><<<■ 



THE INHERITANCE OF DISEASE * 

 PAUL A. LEWIsf 



Considered in a broad and untechnical sense, an individual's inheritance 

 means all those attributes both actual and potential received at or before 

 birth from the parents. This usage has of late years been given up by scien- 

 tific men in favor of a more circumscribed one, namely, that the in- 

 heritance consists of those attributes actual and potential acquired at the 

 moment of conception due to the intrinsic properties of the germ cells. 



* Reprinted from Human Biology and Racial Welfare, edited by Edmund V. 

 Cowdry with the permission of Paul B. Hoeber, Inc. Copyright 1930, by Paul B. Hoe- 

 ber, Inc. 



t Died of yellow fever at Bahia, Brazil, on June 30, 1929, while investigating the cause 

 of the disease. — Ed. 



