174) THE AUDITORY NERVE AND COCHLEA, BY W. WALDEYER. 



gave the first description of such pale nerve fibrils from the 

 cochlea ; and I am inclined to regard as external radial fibres 

 all those extremely fine varicose fibrils which are met with in 

 the sulcus spiralis internus, in addition to the thicker fibres 

 going to the internal hair cells, even if, as in fig. 333, they 

 apparently pass to the internal hair cells, as they must all 

 pursue this direction. The same applies to the fine fibres seen 

 in fig. 335 A, which run upwards in the granule layer, and 

 between the internal hair cells ; for, as above mentioned, those 

 fibres which I distinctly saw terminating in the internal hair 

 cells are far thicker. The varicosities of the external radial 

 fibres (see also fig. 17, p. 148, vol. i.) cannot be mistaken for 

 anything else; and whoever has but once seen these varicose 

 nerve fibrils of the cochlea, will not readily confound them 

 with connective-tissue fibrils. Unquestionably we do here and 

 there see small granule-like enlargements in tolerably regular 

 sequence in the extremely delicate connective-tissue fibrils of 

 the tympanal surface of the basilar membrane, but these never 

 have the peculiar lustre and exquisite drop-like form of the 

 true nerve varicosities. With regard to these two peculiari- 

 ties, as well as to the circumstance that the drops assume a 

 blackish tint when macerated in perosmic acid, 1 might suggest 

 that the true nerve varicosities are the expression of an ex- 

 tremely delicate medullary sheath, which would thus not be 

 absent in the primitive fibrils of Max Schultze my axis fibrils. 

 Hasse, on the other hand, denies the existence of a medullary 

 sheath in the thick terminal nerve fibrils of the Bird and Frog, 

 but admits the presence of a delicate sheath of Schwann after 

 their entrance into the ductus cochlearis. I have not been ab]e 

 to make any observations favourable to this view, either in 

 Birds or in Mammals. 



The nervous nature of the radial fibres just described, and 

 their termination in the internal and external hair cells, may 

 now, I believe, after the repeated observations made by Gott- 

 stein and myself, be accepted as a fact, in our knowledge of 

 the cochlea. I am convinced that no one who works with a 

 good method can deny its truth. The question may, however, 

 be reasonably asked, whether other nervous elements and I 

 refer in particular to the spiral fibrous bands of Max Schultze 

 do not also occur in the cochlea ? 



