STRUCTURE OF THE WALL OF THE LABYRINTH. 1)7 



and other tests, it presents the appearance of a granular slightly 

 striated membrane. It is demonstrable in the utriculus, but 

 is there reduced to an extremely thin uniform layer. 



The papilliform processes* <on the inner surface of the 

 tunica propria must, in my opinion, be regarded as normal 

 structures in the adult Man. They are so constant that I 

 almost regard their absence as an evidence of disease. They 

 are limited to certain parts of the wall of the canal, on which 

 account I have elsewhere divided this wall into a papil- 

 lated and a non-papilla ted portion. They appear as transpa- 

 rent spheroidal structures varying greatly in form and size 

 in surface views of the membranous canals of adults,f and in 

 transverse sections are recognisable as projections. They rest 

 with a broad base upon the tunica propria, and project into 

 the lumen of the canal in the form of small clavate or conical 

 processes. 



Towards the tunica propria they have no well-defined line 

 of demarcation, and they must therefore be regarded as con- 

 stituting integral portions of the membrane; especially as they 

 develop from it, and are completely identical with it in struc- 

 ture. In the embryo, and even in the new-born child, the 

 papillae are entirely absent, appearing first at a later period on 

 the inner surface of the wall of the canal opposite the points 

 where the ligaments of the labyrinth are attached exter- 

 nally. The thin portions of the wall of the membranous 

 canals which are adherent to the bone are everywhere com- 

 pletely destitute of papillae. I have never even seen the 

 slightest indication of them at these points, notwithstanding 



* I use the above expression instead of villus-like, which I formerly 

 adopted, because the structures in question resemble papillae rather than 

 villi. Hasse has expressed the opinion that I have mistaken striae shining 

 through the tissue for papillae or villi, a supposition that convinces me 

 that Hasse has never examined the bodies in question in the adult ; for to 

 exhibit the papillae in transverse sections is one of the easiest things pos- 

 sible, and a mistake is impossible. 



t Whether the papillae are identical with the "large spheroids" de- 

 scribed by Pappenheim, at pp. 43 and 44 of his treatise devoted to the 

 histology of the auditory organs, I am unable, from the obscurity of his 

 statements, to determine. 



VOL. III. H 



