5OO THE ORGAN OF SMELL. 



A dense network of lymphatics ramifies throughout the mucous 

 membrane, carrying the lymph to the pharynx and palate. These 

 lymph-vessels may be injected through the subarachnoid space 

 (Key and Retzius). 



The nerves (trigeminal) are widely distributed in the epithelium, 

 ramifying through both the respiratory and olfactory regions. 

 After repeated divisions these nerves lose their medullary sheaths, 

 and end in telodendria which are usually provided with terminal 

 nodules, although some are found which end in mere filaments. 



TECHNIC. 



The nasal mucous membrane is fixed in situ with osmic acid or 

 one of its mixtures, after which small pieces are removed. It should be 

 mentioned that the nonmedullated fibers of the olfactory nerve assume a 

 brownish color under this treatment, while the fibers of Remak do not 

 (Ranvier, 89). 



In order to isolate the epithelial elements, pieces of the mucous 

 membrane are treated with the y$ alcohol of Ranvier. But since the 

 prolongations of the olfactory cells (neuraxes) shrivel and curl in this 

 fluid, Ranvier recommends that, after the epithelial cells have been 

 macerated in ^ alcohol for one or two hours, they be treated with i <f c 

 osmic acid for a quarter of an hour. If shreds be now placed in water 

 and teased, the cells, together with their prolongations, may be isolated 

 without the curling of the latter. 



The chrome-silver method applied to the nasal mucous membrane 

 of young animals and fetuses has been the means of establishing the 

 important fact that the olfactory cells of the olfactory region are in reality 

 peripherally situated ganglion cells. 



