8o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



series are probably all pre-W'hite. The European and American 

 Whites recorded in this connection are all recent, as are also the 

 Chinese, the African Negro, and the 2^Ielanesians. 



Thus the time in which ear exostoses are known to have existed 

 extends back about 2,000 years before the Christian era. But the 

 frequency of the condition in the prehistoric American skulls is a sure 

 index that the beginnings of the affection are much older — which is 

 about all that can safely be said on the subject for the present. 



An even more important question than that of antiquity is that of 

 progression. Have ear exostoses, or have they not, been becoming, 

 however slowly, more frequent ? A reliable answer to this query would 

 go far toward the solution of the problem as to whether or not the 

 process is of a degenerative nature ; but such an answer is not yet 

 possible. 



AGE 



Ear exostoses, the data have shown, are encountered from child- 

 hood to old age, but the maximum frequency of their development 

 ranges from adolescence to middle age. With no known exception, 

 they begin to form only after the parts they involve have reached full 

 development, and this development, as seen in the affected skulls, 

 barring an occasional diminution in the lumen of the meatus has as a 

 rule been quite normal. This regular normalcy of structure and the 

 delayed manifestation of the growths speak against the basic cause of 

 the abnormalities being of a degenerative nature. 



SEX 



Ear exostoses are decidedly more frequent in males than they are 

 in females. This phenomenon, moreover, is common to all races, all 

 human subdivisions. What is the meaning of this marked and gen- 

 eralized sex difference? 



It would be easy to draw heredity into the picture and speculate 

 on its sex dominance and other eft'ects. especially since there is con- 

 clusive evidence that hereditary transmission often does have a part 

 in the spread of these growths. But this method of thinking, with 

 our present knowledge, would lead only to a maze of uncertainties. 



Yet heredity in the wider sense is involved in the problem. The 

 pan-human extension of that something in the system that predisposes 

 to ear exostoses can only be sustained as time goes on through he- 

 redity ; and this generalized deeper heredity apparently finds its eft'ec- 

 tiveness everywhere enhanced in the males. The females on the whole 



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