NERVES AND EPITHELIUM OF THE AMPULLA AND SACCULI. Ill 



which Steifensand has named the " plana semilunaria," also 

 contains fine nerve fibres beneath the epithelium (fig. 310). As 

 the primitive nerve fibres traverse the tunica propria, they 

 approximate each other, becoming very fine in the neighbour- 

 hood of the crista, and losing their double contour. It is not 

 difficult to demonstrate in the ampulla of Fishes that have 

 been treated with perosrnic acid, that a slender pale fibre, con- 

 stituting the direct prolongation of a primitive fibre, as was 

 first stated by Reich and Max Schultze, passes beyond the 

 basement membrane of the ampullary crest without the inter- 

 vention of any ganglion cell, and then divides into a great 

 number of finer fibrils. Appearances of a precisely similar 

 nature are so constantly found in specimens, both when recent 

 and after maceration, that it is impossible to regard them a3 

 the results of manipulation. Hartmann has endeavoured to 

 show that in Fishes the nerve fibres form loops in the crista 

 acustica, though Henle had already disproved this view, which 

 indeed may easily be shown to be erroneous from the examina- 

 tion of fine sections that have been subjected to imbibition. 

 Hartmann's conclusion that the nerve medulla is mechanically 

 forced through the basement membrane, giving the appearance 

 of a divided axis-cylinder, cannot be correct if (1) pressure 

 be avoided, and (2) if openings in the basement membrane 

 which confer upon the nerve medulla its peculiar form, can be 

 demonstrated to be pre-existent. On this point Max Schultze, 

 F. E. Schulze, Odenius, Kolliker, Deiters, Hensen, Henle, and 

 Hasse, all agree in stating that the pale fibres enter the epithe- 

 lial layer as prolongations of the doubly contoured nerve 

 fibres in the epithelium.* According to Max Schultze and 

 Odenius, the pale axis-cylinder alone, but according to Hasse 

 and v. Grimm, their delicate sheaths also, enter the epithe- 

 lium. If, after treatment with perosmic acid, a comparison be 



* Although' Henle considers that the statements of Hartmann are 

 directly negatived, he himself thinks the nerve fibres terminate by 

 pointed extremities at the basement membrane (p. 777). Henle does not, 

 however, hold himself justified in altogether denying the positive state- 

 ments of others in regard to the entrance of the nerve fibres into the 

 epithelium. 



