NO. 6 EAK EXOSTOSES HRDLTCKA I9 



NEW OBSERVATIONS 



In 1910 and again in 1913 the writer made trips to Peru. Owing 

 to some fortunate circumstances and with the invaUiable aid of the 

 Peruvian authorities, he was able to make large skeletal collections 

 which, aside from a mass of other parts of the skeleton, comprised 

 approximately 4,000 skulls (Hrdlicka, 1911. 1914). These proceeded 

 mainly from the coasts but in an important degree also from the moun- 

 tains. A portion of this material was used in 191 5 in the preparation 

 of the anthropological exhibit for the Panama-California Exposition 

 and remains in the San Diego Museum ; the rest is preserved in the 

 National Museum at Washington. 



Even in the field I was struck by the frequent presence in the outer 

 half of the external auditory meatus of bony swellings and in some 

 cases distinct tumors that more or less restricted or even almost 

 closed the ear opening. In the report on the second expedition 

 (Hrdlicka, 1914), I briefly called attention to the fact that "a rela- 

 tively large proportion of the pre-Columbian people of the more cen- 

 tral parts of the Peruvian coast suffered from a greater or lesser 

 occlusion of the external auditory canals by bony tumors." A small 

 series of these crania with ear exostoses was exhibited and remained 

 at San Diego, and another series was placed on exhibit in the Divi- 

 sion of Physical Anthropology at the United States National Museum 

 for demonstration to visiting surgeons. 



In 1921-22, at my instigation, the series of Peruvian skulls in the 

 United States National Museum was examined for the bony tumors in 

 question by Dr. Beatrice Bickel. During these examinations and 

 especially when an attempt was made to prepare the results for publi- 

 cation, it was found that the subject was more complex than at first 

 anticipated and that some needed data were not obtained, which led 

 to a second study of the whole series by Dr. Paul Van Natta, then 

 Aid in the Division of Physical Anthropology of the Museum ; and 

 as the results of this second study differed somewhat from those of 

 the first, a larger part of the collection was submitted to a third ex- 

 amination by myself. The results differed slightly from those of both 

 previous examinations, but the differences in the three were seen now 

 to be mostly only those in the precise appraisal of the various grades 

 of the abnormality, the essentials remaining fairly constant. 



Subsequently, finding the condition repeatedly also in other Indian 

 and even in some non-American skulls, I extended the personal ex- 

 amination to a number of series of crania in the National Museum 

 collections. Then other work intervened, and the publication of the 

 results had to be postponed. 



