42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



conditions, evident or not, there may set in a relatively rapid enlarge- 

 ment, which soon is attended by distressing symptoms that bring the 

 subject to the aural surgeon. 



An interesting further fact is that after an operation and removal 

 of an ear exostosis, in a majority of cases the subject remains free 

 from the growth, but in some cases there is a recurrence of the bony 

 tumor. In the absence of both infection and malignancy the latter 

 event implies, it would seem, a special neuro-vascular influence. 



SUBDIVISION 



Since Toynbee (i860), repeated but not very successful efforts have 

 been made at a classification of ear exostoses, either on the basis of 

 causation, of the form of the tumors, or of their structure. 



The morphological classification alone needs to be dealt with in this 

 section. It begins with Cassells (1877), ^^^^ divides the growths into 

 two categories, namely, the hyperostoses and the exostoses, which he 

 believes to be separate abnormalities and of totally different origin. 

 This clinically convenient subdivision, notwithstanding voices to the 

 contrary and its demonstrable basic inaccuracy, has become generalized 

 in otology and will probably stay there. Von Troeltsch (1881, p. 144) 

 states that hyperostoses are not clearly separable from exostoses, yet 

 he uses the two terms, applying the first to " a generalized hyperplasia 

 of the walls " of the meatus. Virchow, though in general admitting the 

 subdivision, appears at times uncertain; he speaks (1889) of a "hy- 

 perostosis " in a Tanimbar skull which closely resembles the " ex- 

 ostoses " of the Peruvians. 



Kessel (1889) follows Cassells, but adds two more forms and gives 

 the following somewhat arbitrary definitions : Hyperostoses, involv- 

 ing the whole extent of the canal ; exostoses, more or less circum- 

 scribed growths ; periostoses, ringlike bony growths ; and osteophytes, 

 spinous growths. 



Pritchard ( 1891 ) attempts to divide ear exostoses into : i. multiple, 

 uniformly smooth and rounded ; 2, multiple, irregular in shape ; and 3, 

 single, polypoid. 



Hartmann (1896, p. 44) has this to say: 



Now as it happens that of late years both hyperostoses and exostoses have 

 been described indifferently under the title of exostoses, although they are 

 plainly two different processes ; the descriptions of cases vary a great deal, 

 depending on whether the author has had his mind more intent on exostosis or 

 on hyperostosis. That there is an essential difference between the two, is also 

 supported by Virchow, who. with his enormous experience with exostoses, 

 remarked, during the discussion of a paper which I had read in the Berlin Medi- 

 cal Society : " I agree with the reader, particularly in one point which made 



