258 PROBLEMS OF HUMAN EVOLUTION 



that obscure it altogether. In England and Wales the ratio of 

 the deaf and dumb to the general population was in 



1851 I to 1738 

 1 86 1 I to 1640 

 1871 I to 1972 

 1881 I to 1954 

 1891 i to 2043 1 



In these figures the congenitally deaf and those whose deaf- 

 ness has resulted from disease or accident are counted indis- 

 criminately and the reduction due to the decrease and better 

 treatment of typhus, scarlet fever, measles and other diseases 

 has more than counterbalanced the increase of congenital deaf- 

 ness. There is every reason to believe that this is the explana- 

 tion of the figures, though absolute proof is not as yet obtainable 

 in England. However, the facts that have been established in 

 the United States leave no doubt as to the tendency. 



The specific infectious diseases that often leave deafness as a 

 legacy are always at work and it is important to understand 

 what results follow from their working. They often find out 

 a general weakness of constitution of which the resultant deaf- 

 ness is a symptom. Almost certainly in some cases they bring 

 to light a local original defect (such as a tendency to catarrh in 

 the air passages connected with the ear). By producing deafness 

 in days when the deaf seldom left any progeny, they helped to 

 maintain the standard of physique. In the present day they 

 simmer in fetid corners instead of sweeping over whole towns, 

 districts or countries. And thus the unsound are not so much 

 hampered by a congenital defect as they were in the days of 

 raging epidemics and rudimentary science. Moreover the practice 

 of removing adenoids with the result that the sufferer, in many 

 cases, gains much in strength, must eventually increase the 

 tendency to adenoids and so to the deafness that often results 

 from them. 



Civilised peoples are therefore in the presence of a grave 

 danger. The amount of deafness, potential or actual, is in- 



1 Deaf Mutism, p. 2O I . 



