664 Transactions op the American Institute. 



causes of deaf-dumbness. 

 Dr. Peet, Principal of the New York Institution for the Instruc- 

 tion of the Deaf and Dumb, gives, in The Herald of Health, 

 statistics from which he deduces the striking conclusion that in 

 Europe, generally, the chances of the birth of a deaf-mute child are 

 more than twice as great as in the United States, or six hundred 

 and fifteen in a million there, against two hundred and seventy- 

 eight in a million here; while the chances of the loss of hearing 

 after birth are in Europe, except in Germany, much less than in 

 the United States, to wit: one hundred and fifty-four in a million 

 there, and two hundred and twenty-two in a million here. Such 

 statistical results as these form the data from which we must study 

 the cause of deaf-dumbness. This striking contrast between the 

 old world and the new may be owing, in part, to climate; in part 

 to the severe out-door labors imposed on women of the laboring 

 classes in many countries of Europe; in pai't to idiosyncracies of 

 race. The European returns which show such a preponderance of 

 congenital cases, are chiefly from countries where the bulk of the 

 population is of the Celtic and Latin races. We have very few 

 auch returns from European populations of the Anglo-Saxon and 

 Teutonic races, and most of those we have agree with the American 

 returns in presenting a large proportion of accidental cases. The 

 causes of congenital deafness are as yet but very imperfectly under- 

 stood. When deafness is the apparent result of a known disease 

 or accident, it is comparatively easy to judge with probability of 

 the mode of operation; but in most cases of congenital deafness we 

 are left wholly in the dark, even as to the condition of the organs 

 of hearing. They are too deeply seated for more than a very 

 superficial examination in life, and opportunities for dissection of 

 subjects known to have been deaf-mutes rarely occur. 



The remote causes that have been, with most probability, 

 assigned for congenital deaf-dumbness, are the following: 



1. Unequal ages of the parents, especially where the mother is 

 older than the father, or advanced age of either parent, especially 

 of the mother. 



2. Ill health and feebleness of constitution in one or both parents, 

 especially where there is a hereditary tendency to scrofula. 



3. Impainnent of the procreative power, especially in the father, 

 through early dissipation or bad habits. 



4. Intermarriages of blood relations. 



