August 2, 1912] 



SCIENCE 



151 



flowers of the most precious strains in the 

 garden of life are heing plucked before they 

 produce seed. 



The essay on heredity and politics is one of 

 the best in the book. A successful nation is a 

 powerful nation, and the authors conclude: 

 " A ' theory of power ' which takes account of 

 modern biological knowledge in a strenuous 

 effort to improve the physical, mental and 

 moral state of the race, by both environment 

 and heredity, and by their interaction one on 

 the other, seems to us a good basis for polit- 

 ical endeavor." Increasing the men of genius 

 will make possible improved environment, but 

 if racial efficiency fall civilization must de- 

 cline. And the civilized nations spend their 

 substance in caring for the unfit for whom 

 the fit are taxed to such an extent that they 

 can not carry the added expense of children. 

 So it has come about that only the weakling 

 can afford to have children in unlimited num- 

 bers, since the state will care for their chil- 

 dren. The handicap on the fit is too heavy; 

 it is they, and not the unfit, who are, in effect, 

 being sterilized. A governing class becomes 

 such and maintains itself by virtue of its in- 

 herent strong traits. Even in democratic 

 America the opportunities afforded by busi- 

 ness have lured the strongest men into it, and 

 so " big business " has come to constitute the 

 governing class. And as between nations, 

 that which breeds the most of the best blood, 

 while taking advantage of the advances of 

 science and sanitation, will eventually sur- 

 pass the others and inherit the earth. 



C. B. Davenport 



THE INHERITANCE OF SKIN COLOB 

 The mulatto is frequently instanced as a 

 "blend"; and an exception to the Mendelian 

 scheme of inheritance in that he is supposed 

 to breed true. This position, I believe, repre- 

 sents an off-hand judgment based on insuifi- 

 cient evidence or faulty observation. I have 

 seen a number of unquestionable cases of 

 " reversion " to grandparental skin color 

 among the fraternities of mulatto crosses. 

 In numerous instances one of the third gen- 



eration is either darker or lighter than either 

 parent, i. e., he has the skin color of his negro 

 grandmother or his white grandfather, this 

 being the invariable nature of the cross. 



A man is a combination of thousands of 

 characters; skin color is only one of these. 

 When one considers the offspring of mulattos 

 one must remember that such may have a 

 negro skin associated with a European nose, 

 or negro lips with white skin. One meets 

 with plenty of mulattos that from the stand- 

 point of skin color alone are white, brunette 

 or blond; but one is not deceived as to their 

 extraction since negroid features appear in 

 combination. The probable explanation of 

 the general opinion that mulattos breed true, 

 contrary to the Mendelian principle of segre- 

 gation, is due to this fact of failure to dis- 

 sociate skin color from other facial character- 

 istics. The Davenports' cite five cases of un- 

 doubted segregation of skin color in the third 

 generation. Such families are fairly com- 

 mon in the south. I have shown, moreover, 

 that histologically there is no difference be- 

 tween the skins of blonds, brunettes, mulattos 

 and negroes, except in the abundance of 

 identical pigment granules.^ Histologically, 

 many mulatto skins can not be told from 

 brunette skins. 



The heredity of skin color in crosses be- 

 tween negroes and whites unquestionably fol- 

 lows Mendelian laws. The mulatto shows the 

 dominance (frequently imperfect) of the 

 deeper pigmented condition. In the next- 

 succeeding generation there is again a segre- 

 gation of negro and white skin colors.' The 

 fact, however, that the first generation of 



' Am. Nat., Vol. 44, 1910. 



= Am. Nat., Vol. 45, 1911. 



' The same is true with respect to an extensive 

 Indian-negro cross which occurred in Amherst and 

 Nelson counties, Va., resulting in the loss of an 

 entire Indian tribe. I am told that in many 

 families one or several of the children are dis- 

 tinctly more Indian or more negro than the prev- 

 alent type of the cross. Here again the negro skin 

 color seems dominant to the Indian; on the con- 

 trary, the Indian type of hair apparently domi- 

 nates over the kinky negro hair. 



