CONTROVERTED POINTS; HISTORICAL NOTICES. 187 



points as appear to us to be of importance. It is not the object of 

 this work to give in full detail all the innumerable opinions that, just 

 as in the case of the retina, have been advanced on every point of 

 structure in the cochlea. 



In the first place, it must be mentioned that Deiters (13), Lowen- 

 berg (37 39) and Henle (26) consider that the membrana tectoria is 

 firmly attached to the outer wall of the ductus cochlearis, in close 

 proximity to the ligamentuin spirale accessorium. Gottstein and 

 myself have never seen anything of the kind in many excellent sec- 

 tions of the cochlea prepared in gelatine ; nor have Kolliker (30), 

 Middendorp (40), and Rosenberg (49). Moreover, the drawings of 

 Lowenberg and Henle do not coincide with one another ; the fourth 

 cochlear canal of Lowenberg ("canal que j'ai decouvert," Lowenberg), 

 Henle's "upper chamber," must consequently be given up. Deiters (13) 

 and Henle (26) have given the most detailed description of the crista 

 spiralis. The former represents the small epithelial cells as connec- 

 tive tissue. Hensen (27), with whom Kolliker (30) and Middendorp 

 (40) are inclined to agree, considers the matrix of the crista, which I 

 have described as osteoid substance, to be an epithelial excretion. 

 The connection of the warts of the crista with the teeth was first 

 demonstrated by Henle (26), who also pointed out the tubercle-like 

 thickenings on the tympanal surface of the membrana basilaris. Of 

 the two forms of the lamina reticularis described by Henle (26), I am 

 only able to recognize the second as normal ; his first one results 

 from the breaking up of the second. The lamina reticularis is always 

 best seen in perfectly fresh specimens. 



Henle (26) has also described two different forms of the internal 

 pillars, in reference to which I must express myself in favour of the con- 

 trary statements of Middendorp (40). The latter, however, maintains 

 with Deiters (13) that the pillars are hollow ; actual transverse sections, 

 which have frequently come under my observation, both in Gottstein's 

 and my own preparations, prove them to be completely solid struc- 

 tures, appearing as if composed of fasciculi of fibres. In opposition to 

 the statement lately reiterated by Kolliker (30), that the external 

 pillars form varicosities, I can only say positively that I have never 

 observed such appearances under any circumstances, nor is this at 

 the present time a matter of any moment. 



Lowenberg describes processes at the lower end of the internal hair 

 cells, which branch and communicate with the processes of the granule 

 cells. I have not, however, been able to see them. 



Deiters (13) has supplied the most exact description of the external 

 hair cells. All subsequent investigators of the cochlea of Mammals have 



