NO. 6 EAR EXOSTOSES HRDLICKA 7 



in the old Peruvians may be explained through the action of two 

 causes, the peculiar compression of the outer part of the canal in the 

 brachy- and hyper-brachychephalic [i. e., deformed, flat-head] skulls, 

 and especially a given tendency towards excessive bone growth, such 

 as is manifested through multiple exostoses." ° 



The same year (1894) George Dorsey reports, in his paper on the 

 *' Crania from the Necropolis of Ancon, Peru ", 4 crania with ear 

 exostoses among 58 skulls of males (near 7 percent), and 2 among 28 

 undeformed skulls of females (a little over 9 percent) ; but the report 

 is of a somewhat casual nature and probably does not fully represent 

 conditions in this respect as they existed in the series of skulls Dr. 

 Dorsey examined. 



Bezold (1895) reports the frequency of ear exostoses in over 19,000 

 White (mainly German) patients with ear troubles to have been 

 0.6 percent. 



A brief report on ear exostoses in American crania is made by Ten 

 Kate (1896). In 50 crania from various localities on the coast of 

 Peru he found 4 with ear exostoses ; in 1 10 Calchaqui skulls of north- 

 western Argentina there was none with such a formation. In view of 

 his evidence he is strongly of the opinion that cranial deformation 

 has no connection with the bony tumors. 



The same year Von Luschan, in dealing with various defects and 

 deformations in the external auditory meatus, particularly in deformed 

 skulls from Peru and Argentina, touches also on the meatal hyper- 

 ostoses and exostoses. He gives no new data, but expresses the opinion 

 that these conditions cannot be attributed to head deformation, for 

 on one hand they are absent from many of the most deformed skulls, 

 and on the other they occur also in skulls that have no deformation. 

 The real causes of these bony growths are uncertain; in individual 

 cases they may perhaps originate in consequence of the constant drag 

 produced by heavy ear pendants and great enlargement of the lobule. 



erscheinen, dass wir in dieser besonderen, kiinstlich geschaffenen Raumveran- 

 derung und Beschrankuiig ein Irritamentum zu suchen haben, welches das 

 wachsende Os tympanicum in seiner normalen Entwicklung derartig zu storen 

 vermochte, dass es, bei einer aus irgend welchen anderen Griinder vorhandenen 

 Disposition zur Exostosenbildung, iiberhaupt an Stellen welche zur Ossification 

 schritten, excessiv wucherte und somit Exostosen des ausseren Gehorgans 

 erzeugte." (P. 274.) 



" "Aus dem besonderen Zusammenwirken zweier Momente, der eigenartigen 

 Verdriickung des ausseren Gehorgans bei den brachy- und hyperbrachycephalen 

 Schadeln und einer gegebenen Neigung zu excessivem Knochenwachsthum iiber- 

 haupt, wie sie durch die Exostosis multiplex zu Tage tritt, wiirde sich somit das 

 so auffallend haufige Vorkommen von Exostosen des ausseren Gehorgans bei 

 den alten Peruanern erklaren lassen." (P. 275.) 



