26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



very little if any connection with senility and its disorders — another 

 point of importance. 



It should be borne in mind, moreover, that the clinical age rei)orts 

 embodied in the above data are the ages at the time the subjects applied 

 for treatment, and that in all the cases the bony growths in the ear 

 began earlier. The data therefore show the ages at which the tumors 

 reached development that caused the patient to apply for relief. Should 

 we wish to learn the age at which the ear exostoses began, it would 

 be necessary to shift the whole scale of ages in the direction of less 

 years. How much to shift, on the average, cannot be estimated. In 

 individual cases ear exostoses were known to the patients to have 

 existed for many years before they gave sufficient trouble to lead the 

 subject to the aural surgeon. The matter can only be settled, it would 

 seem, by prolonged future attention to this point. 



Ah^7V observations. — Excluding the Eskimo, the specimens in which 

 both meatus cannot be examined, and the very young, there are in 

 the National Museum 335 skulls of Indian children between the ages 

 when the tympanic portion is fully added to the bony ear and when 

 there occurs the eruption of a permanent J\L. — in other words between 

 about 2 and 12 years of age. The material, like that of the adults, is 

 mainly pre-Columbian, and a good proportion of the skulls show one 

 or another of the three kinds of deformation. A careful scrutiny 

 of these specimens showed 334 without any trace of ear exostoses. 

 The sole specimen showing the abnormality was a pronounced " flac- 

 head " from Santo Domingo, with lateral permanent upper incisors 

 and permanent upper molars about to erupt — hence about 8 to 9 years 

 of age. In the left meatus of this skull is seen on the posterior wall, 

 tympanic part, a small but distinct abnormal nodule, which in all 

 [probability would have later grown to a definite exostosis. 



It may thus be concluded that, among the old American Indians at 

 least, tympanic exostoses did not develop, or did so but exceedingly 

 rarely, in childhood. 



Even in the Indian adolescent of our collections, however, these 

 growths are not very evident. They belong essentially to the earlier 

 half or two-thirds of the adult life, though they not seldom begin 

 before the adult stage is reached. Their maximum frequency and 

 development in the Indian belong principally to the ages of about 

 30 to 60. They are infrequent in older sulijects and, as in Whites, it 

 is plain that they have little if any relation to senility and its path- 

 ology. All of these facts are of etiological importance. 



