NURTURE AND NATURE 27 



It will be seen that, if we exclude strabismus, the diseases of eye and eyelid 

 do not produce half the effect on vision that refraction does. 



Now I do not intend to argue for a moment that the Edinburgh data 

 provide the final word in these matters, but they form the first solid attempt 

 to provide information as to the influence of home environment. Neither the 

 school medical officer nor, as a rule, the teacher can follow the children into 

 their homes. All that has hitherto been done has been more or less plausible 

 guesswork as to the relation of home environment to the health and intelligence 

 of the child. I shall not be surprised to find, when further data are available, 

 that the nation has for years been putting its money on "Environment" when 

 "Heredity" wins in a canter. To say this is not to discourage all attempts 

 to better defective sight in the schools or to check the intensification of myopia. 

 But it would be foolish in face of our increasing degeneracy to neglect the 

 possibility that only a complete change of our methods for social improvement 

 can in the long run hinder the spread of defects. Better qualities, such as 

 keen and strong vision, are no longer an absolute requisite for survival, and 

 defectiveness, instead of meeting the stern judgment of Nature, is by govern- 

 mental and charitable agencies supported to multiply its kind. The curative 

 art in its tenderness for the individual may be disastrous for the race, unless it 

 realizes fully the relative biological importance of heredity and environment. 



APPENDIX B 

 CLEANLINESS AND VISION 



Through the courtesy of Dr F. E. Rock, School Medical Officer of the 

 Edmonton Education Committee, I have received data connecting the age, 

 acuity of vision, and cleanliness of body and clothing of 953 Edmonton 

 children. Statistically the data are somewhat erratic as there has been an 

 age selection in testing the eyesight and clearly home environment, if we are 

 to measure that by cleanliness of body and clothing, also produces an age 

 selection. Dr Rock, as many another medical officer, not unnaturally, takes 

 this cleanliness as the only measure available of home environment. Remem- 

 bering what children are and will do, I must submit that it can never replace 

 actually study of the homes and the parents. Taking it, however, as a measure 

 of home environment, Dr Alice Lee provides me with the following correlations : 



Age and acuity of vision - -037 



(i.e. the vision is slightly worse for the elder children). 



Age and home environment + -029 



(i.e. the cleanliness is slightly better with the elder children). 



Acuity of vision and home environment + -072. 



