492 THE ORGAN OF HEARING. 



fiber, the snstentacular fiber, and which is found partly within and 

 partly without the cell. The sustentacular fiber begins near the 

 center of the thicker basal portion of the cell-body and extends first 

 into the cell itself, then passes to the surface, and, entering the 

 phalangeal process, passes to the top of the cell and expands as a 

 plate, to which the name phalangeal plate has been given. The 

 latter is broader than the phalangeal process, and since, as we shall 

 see, the phalangeal plates are joined to one another, as well as to 

 the elliptically shaped cuticular zones of the outer auditory cells, 

 there remains a space between the cells of Deiters and the auditory 

 cells, as also between the outer pillars and the innermost of the 

 outer auditory cells, known as Nuel's space. To the basal regions 

 of the inner row of the cells of Deiters is joined the basal plate of 

 the outer pillars of the arches of Corti. 



Next to the outer row of Deiters's cells are the cells of Hensen, 

 arranged in about eight radially disposed rows. They form an 

 eminence which is high internally, but gradually decreases in height 

 externally. The somewhat narrowed bases of Hensen's cells prob- 

 ably extend, without exception, to the basilar membrane. The free 

 surfaces of these cells are likewise covered by a thin cuticular mem- 

 brane. In man the cells of Hensen usually contain yellow pigment ; 

 in the guinea-pig, as a rule, fat ; and in the rabbit, generally rudi- 

 ments of sustentacular fibers. Externally the cells of Hensen graduv 

 ally change into elements of a more cuboid type the cells of 

 Claudius, of which there are about ten rows, radially disposed. The 

 surfaces of the latter also possess a cuticular margin ; the nucleus is 

 at the center of each cell and pigment is also present. Darker 

 elements with more basally situated nuclei sometimes occur be- 

 tween these cells, giving rise to the appearance of a double-layered 

 epithelium (Bottcher's cells). 



Thus far we have considered in detail the cells comprising the 

 organ of Corti, and described their relative positions and sequence 

 from within outward. In order to give a clearer understanding of 

 the mutual relations of these cells, from within outward and in the 

 direction of the spiral turning of the cochlea, we shall now consider 

 the appearance presented in a surface view of the organ of Corti. 



From within outward a surface view of the organ of Corti pre- 

 sents the following characteristics : The somewhat broadened hex- 

 agonal outlines of. the inner sustentacular cells adjoin the epithelial 

 elements of the sulcus spiralis internus and terminate externally in 

 a spiral undulating line (if seen for only a short distance, this line 

 appears straight). On this line border the contours of the cuticular 

 zones belonging to the inner auditory cells. The outer margins of 

 the cuticular zones come in contact with the head-plates of the 

 inner pillars, the cuticular zone of one inner auditory cell coming in 

 contact with at least two head-plates. The externally directed pro- 

 cesses of the head-plates belonging to the inner pillars come in 

 contact with one another and end in a spiral line which for a short 



