136 PRACTICAL HISTOLOGY. 



The cells of Corti will be easily seen external to the 

 outer rods. There are three rows in the cat and some 

 other animals, four in man. Each cell has short stiff hair- 

 like processes on its upper extremity projecting through the 

 membrana reticularis. A process passes from the lower end 

 of the cell to be attached to the basilar membrane. Out- 

 side Corti's cells the epithelium is columnar, but without 

 hairs. It gradually becomes short and cubical, and so 

 passes gradually into the epithelium lining the outer part of 

 the scala media. 



The membrana basilaris may be seen stretching from 

 the lamina spiralis ossea to a fan-shaped (in V. S.) expan- 

 sion the ligamentum spirale of Kolliker (the cochlear 

 muscle of Bowman). The tissue of the ligament is 

 peculiar, and it is difficult to say what is precisely its 

 nature. 



The membrana tectoria may be seen extending from the 

 limbus lamina spiralis over the heads of the rods and the 

 hair . cells. In the normal condition it appears to hang 

 free above these, but very often in prepared cochleae it lies 

 closely upon the hair cells. According to Waldeyer it con- 

 sists in the unhardened cochlea of a soft pulpy material. 



The membrane of Reissner may perhaps be found. It 

 consists of a single layer of flattened epithelial cells separat- 

 ing the scala media from the scala vestibuli. 



The spiral ganglion may be seen in carminised sections 

 within the bone of the spiral lamina. 



c. (H.) A preparation showing a superficial view 

 of Corti's organ ; the heads of the rods resembling a row 

 of pianoforte keys ; the membrana reticularis consisting 

 of plates that have the form of rings and phalanges. The 

 hairs of Corti's cells project through the rings. 



SCHNEIDERIAN MEMBRANE. 



243. Examine (H.) a preparation of olfactory cells from 

 the nose of the newt, prepared thus : Harden the head in 

 Miiller's fluid for four or five days. Snip out the upper part 

 of the nostril. Scrape the mucous membrane of the detached 

 portion with the point of a scalpel. Dissociate with needles, 



