236 HEREDITY AND EUGENICS 



ear defects were about half as common as in whites, 

 and there were fewer cases of metabohc disturbance, 

 such as diabetes and urinary calcuh. It thus appears 

 that the negro is a better animal as far as e3'es and 

 ears are concerned, has a more protective skin and 

 a less easily deranged metabolism, but is less resistant 

 to diseases of the lungs and pleura and to some of the 

 general diseases. 



Discussing the results of the mingling of races in 

 the United States through immigration, Davenport 

 (191 7) states that nearly two-thirds of the 9,000,000 

 population of New York State are foreign born, or of 

 foreign or mixed parentage. Nearly all the European 

 countries are represented, most of them b}' many 

 thousands, and intermingling of races in the country 

 at large is taking place on a scale never before ap- 

 proached in the histor}- of man. The irregular 

 dentition which makes orthodontia a recognised 

 branch of dentistry may be a result of disharmonies 

 between teeth and jaws in the various crossed races, 

 a condition in marked contrast with the regular 

 dentition of native races, though such conditions may 

 also arise from malnutrition. Davenport concludes 

 that miscegenation commonly results in disharmony 

 of physical, mental, and temperamental qualities, 

 often leading to disharmon}' with the environment 

 and consequent unhappiness. A hybridised people 

 will tend to be restless, dissatisfied, and ineffective; 

 the high death-rate in middle life ma}'^ be due to bodil}' 

 maladjustments, and much of the crime and insanity 

 to the inheritance of badh' adjusted mental and 

 temperamental differences. It is probable that in 

 such a very heterogeneous mixture, in which there 

 has been, until recently, little selection or often even 

 negative selection of the original immigrant elements, 

 the disadvantages and disharmonies more than offset 

 any advantages that may accrue from crossing. To 



