QUESTION OF PHYSICAL DEGENERATION 263 



We see now (l) that though sight in London Board School 

 children is very often defective, it is seldom seriously so ; (2) 

 that the defect is believed by ophthalmologists to have in most 

 cases a congenital basis, though it may be aggravated by bad 

 conditions. 



Dr Carter concludes by stating his conviction that many cases 

 of subnormality cannot be accounted for by the imperfection of 

 the apparatus of accommodation, the apparatus for throwing the 

 image on the sensitive plate, but that the retina must be at fault. 

 The failure of the retina he attributes to want of practice in 

 examining things closely. But why should there not be con- 

 genital defect here also ? If it occurs in one part of the optical 

 machinery, it is likely that it should occur in another. One fact 

 which he mentions is clearly a sign of the times. "Both 

 convex and concave spectacles are quite commonly used by 

 children requiring them, and parents seem to have been alive to 

 the fact of defective vision in its higher degrees and to have 

 sought assistance from hospitals for its relief." l The wearing 

 of spectacles by the children of the poor is surely a very recent 

 phenomenon. In former generations no such aid was obtainable, 

 and to this we may attribute the fact that the defect as a rule 

 amounts only to such mild subnormality as will not put a man 

 at a great disadvantage. There must have been some elimination 

 of a high degree of bad sight, probably in part through the 

 agency of sexual selection. The conditions have only in recent 

 years become suitable for the spread of serious abnormality. 



The subjects discussed in this section have brought out very Summary 

 clearly the working of pammixis. A character that is no longer 

 protected by Natural Selection is wanting in some individual. 

 From this no visible result may follow for a generation or two. 

 But there has been a loss of stability : the descendants of this 

 individual have in their pedigree an ancestor with the defect in 

 question and reversion may revive it. A few more cases of the 

 same defect in the same family or small group, and stability is 

 gone. At first the species seems to suffer but little : defect 

 shows itself in an individual here and there. But when once the 



1 Dr Carter's Report, p. 14. 



