776 



THE NOSE. 



leps numerous in the meuVbraue lining the several cavities which communi- 

 cate with the nasal fossse. 



The olfactory region or that in which the olfactory nerve is distributed, 

 includes the upper and middle turbinated parts, and the upper portion 

 of the septum. Its mucous membrane is thicker and more delicate in 

 consistence than that of the ciliated region, being soft and pulpy. The 

 columnar cells on its surface are prolonged at their deep extremities into 

 threads, which have been observed to communicate with stellate cells of 

 ihe connective tissue. Beneath the columnar cells is a considerable thick- 

 ness of densely nucleated tissue, compared by Henle to the cortical brain- 

 substance. The glands of this region are numerous ; but are of a more 

 simple structure than those in the lower part of the fossae. 



Fig. 535. CELLS AND TERMINAL NERVE-FIBRES 

 OP THE OLFACTORY REGION (from Frey after 

 Schultze). 



1, from the frog ; 2, from man ; a, epithelial 

 cell, extending deeply into a ramified process; 

 b, olfactory cells ; c, their peripheral rods ; 

 e, their extremities, seen in 1 to be prolonged 

 into ciliary hairs ; d, their central filaments ; 3, 

 olfactory nerve-fibres from the dog ; a, the 

 division into fine fibrillse. 



Olfactory Cells. Intermixed with the 

 columnar epithelial cells of the olfactory 

 region, and so numerous as to surround 

 each of them, are certain peculiar bodies, 

 each consisting of a spindle - shaped 

 nucleated cell, from which proceed a 

 superficial and a deep process. The 

 superficial process is a cylindrical or 

 slightly tapering thread passing directly 



/7 ^BIKflflMi^! ' mt ' m * ^ ne sur ^ ace ) an d terminating abruptly 

 f IfMO at the same level as the epithelial cells 



I '*Wwf^ ^t between which it lies : the deep process 



A I3P1 * s more s l en der an d passes vertically 



invrards. Both processes frequently pre- 

 sent a beaded appearance similar to that 

 observed in fine nerve - filaments, and 



considered to be of a similar accidental origin. It was suggested by Max 

 Schultze, the discoverer of the olfactory cells, and is highly probable, that 

 the deep processes are directly continuous with the filaments of the olfactory 

 nerve, but the continuity does not appear to have been actually observed. 



The superficial process of the olfactory cell was observed by Schultze to be sur- 

 mounted by a short stiff hair-like process, and has been so described by others ; but 

 both the discoverer and others are now agreed that this appearance results from the 

 coagulation of albumen escaped from the interior of the process. Long and fine hair- 

 like processes do, however, exist on the olfactory membranes of amphibia, reptiles, 

 and birds, and had been previously pointed out by Schultze. 



Olfactory Nerve. The filaments of this nerve, lodged at first in grooves 

 on the surface of the bone, enter obliquely the substance of the Schneiderian 

 membrane, and pass to their distribution between its mucous and fibrous 

 layers. The nerves of the septum are rather larger than those of the outer 

 wall of the nasal fossse ; they extend over the upper third of the septum, 



