80 



THE EUSTACHIAN TUBE, BY PROFESSOR RUDINGER. 



The histological characters of the raucous membrane are as 

 follows : Its internal surface is lined throughout by a lami- 

 nated ciliated epithelium, which has an average diameter of 

 O020 of a millimeter. In this, as well as in the osseous portion 

 of the tube, two kinds of cells may be distinguished : (1) Those 



Fig. 294. 



Fig. 294. Transverse section of the Eustachian tube of Vespertilio 

 murinus . 1, Median cartilaginous lamina ; 2, thinner uncinate pro- 

 cess ; 3, oral-shaped safety tube ; 4, auxiliary fissure ; 5, elongated 

 quadrangular air sac ; 6, musculus levator veli palatini ; 7, thick 

 glandular layer ; 8, excretory duct of a gland. 



which stand in close order on the free surface, and which when 

 they possess cilia are broad, and dip with their attenuated 

 extremities (2) into the deeper layer of cells. The cells forming 

 the latter layer rest by a broad base on the basement mem- 

 brane, and s.nd their attenuated extremities between the cells 

 of the superficial layer. The nuclei of the former are elon- 

 gated, those of the latter more spheroidal, as well as smaller 



