LECTURE I 1 



NATURE AND NURTURE IN MENTAL 



DEVELOPMENT 



By F. W. MOTT, M.D., F.R.S. 



Pathologist to the London Coioity Asylums 



The problem of nature and nurture in mental development is 

 one that has recently acquired importance for various reasons, 

 such as the increase of certified insanity and the enormous sums 

 of money spent on asylums for housing lunatics; and the recog- 

 nition by the public that insanity, epilepsy, and feeble-mindedness 

 are in great measure due to inheritance has lead to a widespread 

 feeling that some check should be placed upon propagation of 

 the mentally unfit. This is becoming daily more manifest from 

 two causes : The migration and emigration of the mentally 

 and physically fit from the rural districts and the sedimentation 

 of the unfit in the slums of our large cities where degraded 

 pauperism exists to so great an extent. 



The rapid growth of population in this country commenced 

 with the growth of industrialism and the rise of towns and cities 

 with inhabitants engaged in factories and manual occupations, 

 where individualism necessarily became subject to collectivism. 

 Just as in the human body there is differentiation of structure 

 and function, so there is in the modern complex social organism ; 

 and just as in the human body the failure of function of one 

 organ may disturb the harmony of function of the whole body 

 and mind, so in the social organism a strike, even by a humble 

 section of it, may lead to disorganisation of the whole. 



The collection of large numbers of people in towns and cities 

 who were previously accustomed to individualism in matters of 

 sanitation led to a most deplorable state of affairs, and Sir Edwin 

 Chadwick, a pioneer in sanitary science, in whose honour these 

 lectures were given, was the first to call attention to the necessity 

 of legislation to remedy the growing evil. 



In 1842 a report was published by him on "The Sanitary 

 Condition of the Labouring Population of Great Britain." In 



1 The Chadwick Public Lectures, 1913. 

 291 



