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In addition to those affections of the visual apparatus- 

 depending upon mechanical causes, and those abnormalities 

 of vision, whether of the nature of anaesthesia or hyperaes- 

 thesia and which are all, in every degree, hereditary there 

 can be no doubt that the majority of cases involving the 

 eyelids are also hereditarily transmissible, or at least that a 

 predisposition to them is very frequently transmitted from 

 parents to children. To this latter class belong epicanthus, 

 ptosis, entropion, ectropion, trichiasis, hordeolum, ophthalmia 

 tarsi, cysts, warts, and naevi. There is, in fact, no form of 

 ocular abnormality, whether visual or palpebral, which may 

 not be inherited, or to which a predisposition may not be 

 transmitted. 



With regard to morbid affections of the ear, as in the case 

 of the eye, they may consist of either anaesthetic or hyperces- 

 thetic peculiarities, and these may be equally transmitted. 

 I have already discussed the heredity of deaf-muteness, and 

 would here only remark that it should be remembered that 

 in those cases in which deaf-muteness is not inherited, it may 

 be transformed into an infirmity of some other kind, as 

 hardness of hearing, obtuseness of the mental faculties, or 

 even idiocy (Ribot). How these transformations occur I 

 have already alluded to in previous pages ; moreover, in 

 those cases of musical talent where "a good ear " is essential, 

 the musical aptness necessarily depends upon the heredity 

 of certain qualities of hearing. Of those affections of the 

 ear which are perhaps most frequently inherited, I may 

 mention cophosis nervosa. My accomplished friend, Dr. 

 Macnaughton Jones, who is generally considered an authority 

 on every subject upon which he writes, says, in the last 

 edition of his excellent Practitioner's Handbook of the 

 Diseases of the Ear and Naso-pharynx " That deafness is 



