C72 THE NOSE. 



branches being distributed over the surface of the upper spongy bone, 

 and the anterior branches descending over the plain surface of the 

 ethmoid and the middle spongy bone. 



The nerves as they descend, ramify and unite in a plexiform manner, 

 and the filaments join in brush-like and flattened tufts, which, spreading 

 out laterally and communicating freely with similar offsets on each 

 side, form a' fine network, with elongated and narrow intervals between 

 the points of junction. 



In their nature the olfactory filaments differ much from the ordinary 

 dark-bordered fibres of the cerebral and spinal nerves : they possess 

 no medullary sheath, are pale, and finely granular in aspect, firmly 

 adherent one to another, and have oval corpuscles on their surface 

 (fig. 488). 



The greater part of the mucous membrane of the nasal fosscc is pro- 

 vided also with nerves of common sensibility, derived from branches 

 of the fifth pair : the distribution of these has already been de- 

 scribed. 



Fi!-. 488. 



Fig. 4S8. — Nerve-Fibres from the Olfactory Mucous Membrane (Max Scliultze). 

 Magnified between 400 and 500 diameters. 



From a Iirancliof the olfactory nerve of the sheep ; at a, a, two dark bordered or medul- 

 lated fibres, from the fifth pair, associated with the pale olfactory fibres. 



