178 THE AUDITORY NERVE AND COCHLEA, BY W. WALDEYER. 



structures known in histology. With low powers they appear, 

 as Hensen (27) has already indicated, when he compares them 

 with the molecular layer of the retina, as a finely granular mass 

 resembling a finely fibrous neuroglia. With very high powers 

 they exhibit extremely small and irregular varicosities, which 

 correspond rather to the granular swellings I have already 

 described as occurring in the finest connective-tissue fibrils, and 

 are clearly different from the delicate drop-like varicosities of 

 the radial primitive nerve fibrils. I desire to call particular 

 attention to this difference between the spiral fibres and outer 

 radial terminal nerve fibres, as it is seen both in fresh prepara- 

 tions and in those preserved in perosmic acid. That I have 

 actually had the spiral fibrous bands of the organ of Corti under 

 observation, and have not confounded them in any way with 

 tympanal fibres, will be sufficiently proved by the illustrations 

 numbered 334 and 335A. 



I am unable at present to decide from whence the spiral 

 bands of the organ of Corti arise, or what is their nature and 

 significance. The best insight into their nature may be expected 

 to be obtained from the region of the internal hair cells, this 

 being the point of perforation of the nerve fibres, and seat of the 

 previously mentioned granule layer. Preparations of these un- 

 questionably important parts, teazed out with needles, give the 

 appearances presented in fig. 333. Between the hair cells and 

 the foramina for the nerves is a layer of small round cells 

 with relatively large nuclei and extremely delicate protoplasm, 

 which is seldom preserved in an uninjured condition. These 

 cells, which I have provisionally designated granule cells 

 (" Korn zellen " ), give off processes in various directions that 

 in all respects resemble the fibrils of the spiral bands, and ap- 

 pear also (at eZ) to curve round into these bands.* In longi- 

 tudinal sections of the lamina spiralis (fig. 3 35 A) the elements 

 of the region of the internal hair cells succeed one another in 

 five consecutive layers ; the nerve fibres (e) ; the granule layer 



* Fig. 333 is unfortunately not sufficiently good to show the delicacy 

 of the spiral fibres in question, and their difference from the likewise im- 

 perfectly represented varicose nerve fibrils which I have represented as 

 taken from another preparation at k and I in the figure. 



