SPORADIC CRETINISM 137 



certain that the absence or insufficiency to the function of the thyroid may 

 lead to disturbances of hearing. I refer to the results of thyroid medica- 

 tion that are often attained in a striking manner in these cases. It is just as 

 certain, however, that with complete failure of the thyroid gland the organ of 

 hearing may be completely developed from birth on. Siebermann examined 

 the organ of hearing in Dieterle's cases of congenital thyroaplasia and found 

 entirely normal relationships in an anatomical sense. Even in a functional 

 sense, disturbances do not necessarily have to be present for Maresck's 

 case of thyroaplasia showed no deafness. Hence what is under dispute is 

 only how to explain the disturbances that occur in many cases, v. Wagner 

 was the first to express the opinion that myxedematous swelling of the 

 mucous membrane of the tympanum, the Eustachian tube, etc., could fur- 

 nish the cause of the hardness of hearing. On the contrary, Denker states that 

 thyroidectomized animals after operation are completely deaf, show as the 

 result of histological examination no myxedematous alterations of the 

 mucous membrane and the organ of hearing, nor any degenerative alterations 

 in the nervous organ of hearing or in the bulbar centers. The hypothesis of 

 a dysthyric hardness of hearing (Block) is therefore denied. It is feasible 

 to think, as many otologists assume, that central perception of the stimulus 

 of sound suffers. There is then concerned a form of cortical deafness, or that 

 form of deafness which Heller describes as psychical deafness, in which the 

 perception of words does not come to consciousness, or as Gutzmann suggests, 

 serious defects of attention or a high-grade weakness of memory for speech 

 make their perception of words entirely impossible. Not entirely easy is 

 differential diagnosis from sensory aphasia. The distinction is made possible 

 only by the characteristic signs of feeble-mindedness. One of my cases 

 (case N.) seemed to be deaf-and-dumb. This was striking as otherwise 

 complete hearing mutism [Horstummheit] does not seem to occur in sporadic 

 cretinism. The ear tickling reflex was present. From the side of the spec- 

 ialists, hearing mutism [Horstummheit] was supposed to be present (Dr. 

 Frbschels). The conception of hearing mutism is not, however, uniform 

 among otologists. Gutzmann, Nadoleczny, H. Stern and others speak of hear- 

 ing mutism only when it concerns individuals (mostly children from third 

 to seventh year) who are mute in spite of intact intelligence and intact 

 hearing. These cases of pure hearing mutism are not common. In the case 

 of N. there indeed occurred, after several months' treatment with large doses 

 of thyroidin (to seven tablets a day), a slight, but distinct, degree of ability 

 to hear (lid reflex). Unclear however remains the circumstance that also in 

 complete absence of thyroid gland from birth, deafness does not always de- 

 velop; as has already been mentioned, there occur cases of thyroaplasia that 

 heard. Also I should not neglect to mention that in the numerous dogs on 

 which I myself performed thyroidectomy, and on which later exact investi- 

 gation disproved any existence of accessory thyroids, there were never to be 



