446 A VERS. [ Vo I.. V 1 1 1 . 



nerve to serve in the place of the primitively superficial cells 

 (ancestral hair cells) which have become the bipolar cells of 

 the auditory ganglia. 



5. The system of spiral nerves is composed of fibres within 

 the cochlea which run at right angles to the radial fibres and 

 may or may not be all derived from the radial fibres. Very 

 probably not, as all previous investigators who have accepted 

 the spiral system, have maintained. 



These are the conclusions of Retzius and Van Gehuchten 

 the only investigators who have published results of the appli- 

 cation of the Golgi method to the whole ear. The nerve ends 

 of the maculae and cristae have been studied by another investi- 

 gator, O. Kaiser, who has described the nerve-end as having the 

 form of a calyx, like an egg cup, into which the hair-cell fits. 



In using the Golgi method on the mammalian ear, I have 

 found that success was obtained only when two conditions 

 were observed. The tissue must be free from calcareous 

 matter either in solution or in deposit and it must be placed 

 in the osmium-bichromate mixture alive. Successful stains 

 do not always reward this care, but of other precautions I 

 have no very definite knowledge. These remarks apply to 

 the ear of the sheep, ox and pig in adult condition, and to 

 the ox and pig in embryonic stages, and in this case mainly 

 to the pig. The best results were obtained from embryos of 

 8-14 cm. length as the creatures lie on a scale. The ears 

 were carefully removed from the head, cleaned of superfluous 

 tissue and put at once into a solution of Os. O^. i per cent 

 100 cc. -\- K.2 Cr.y O.y 500 cc. As from 100 to 200 ears were 

 prepared at a time, the work of preparation was shortened as 

 follows. The heads were removed from the embryos to the 

 desired number, then all were sagitally bisected and the brain 

 removed and a third operation shelled out the internal ears 

 which in embryos of this size are still entirely cartilaginous. 

 From 50 to 100 ears were placed in a low but large mouthed 

 bottle of circa 200 cc. capacity, and first well washed off with 

 osmium-bichromate solution once used, which was replaced 

 after a little gentle shaking by a bottle full of the fresh 



