No. I.] THE VERTEBRATE EAR. y^ 



The nerve fibre penetrates the cell and ends in the protoplasm 

 near the nucleus or in the nucleus itself, as he thought he had 

 found. In young animals the nerve may present the appearance 

 of ending bluntly against the side of the cell. This mode of 

 ending is the one almost exclusively figured by Retzius for all 

 the forms he studied, both adult and embryonic. 



The latter author is specially positive that he has never 

 observed anything approaching a penetration of the nerves into 

 the cell protoplasm, and concludes, that the nerve fibre merely 

 applies itself to the surface of the cell wall by a more or less 

 swollen and uneven plate. This contact is not easily destroyed, 

 but Retzius thinks that there is no actual fusion of nerve sub- 

 stance with cell substance. 



He says (237, II), p. 368: "Wie endigen nun diese Fasern .-* 

 Hier bleibt eben die grosste Lucke in unserer Kenntniss vom 

 feineren Bau des Gehororgans. Ich habe mich viellfach bemiiht, 

 diese Lucke auszufuUen, bisher aber fast vergebens. So viel ist 

 jedoch sicher, dass die unteren Enden der ausseren Haarzellen 

 die oberen Fasern der Spiralziige beriihren und ihnen sogar 

 anhaften ; einen directen Uebergang der Nervenfasern in die 

 Haarzellen sah ich aber nie ; nie sah ich die von Nuel beschrie- 

 benen, nach oben zu den Haarzellenden hin emporsteigenden 

 Nervenfasern. Diese Hauptfrage der Histologic des Gehor- 

 organs der Saugethiere muss meiner Ansicht nach noch als 

 unbeantwortet betrachtet werden." While I do not doubt that 

 the last word has not been said on this topic, my own conviction 

 is that in all the vertebrates I have studied, in this particular, 

 spiral nerve courses do not exist, and that the fibres which pierce 

 the floor of the canal make their way as directly as circunstances 

 allow to the morphological bases of the hair-bearing cells and 

 enter into such a union with them that a protoplasmic conti- 

 nuity is established between all living parts of the cell and the 

 nerve end, and that there exists in the cell a specially arranged 

 mechanism for the transfer by transformation of the mass 

 motion of the endolymph into the molecular motion of the 

 nerves. 



Within all of the hair-bearing cells, and apparently running 

 from cell cap to nucleus and from nucleus to basal end of the 

 cell, are to be seen, especially well in cells killed in chromic 

 solution, but also after the reaction of other chemicals, extremely 



