782 



SPECIAL HISTOLOGY. 



ducts are rather more contracted (0-008-0-012 of a line) than the 

 glandular canals, and ascend, always lined by rounded larger cells, 

 straight through the epithelium, in order to terminate on the surface 

 Avith rounded orifices, O'Ol of a line in diameter, surrounded by a few 

 large cells. The tissue beyond these glands is, as in other regions, soft 

 connective tissue, without elastic elements. 



The mucous membrane, in the proper nasal cavities, is very richly 

 supplied with vessels, and less so in the accessory sinuses. The termi- 

 nal branches of these vessels form loose plexuses around the glands, 

 and in the trunks and branches of the olfactory nerves ; while on the 

 surface of the mucous membrane itself, they constitute a more close 

 network with numerous horizontal loops, at first sight leading to the 

 supposition of the presence of ^;a^)z7/ff, which, however, do not exist. 

 The branches, also, of the arteries and veins enter into numerous 

 anastomoses, and constitute (the latter especially) on the "inferior 



Fis. 313. 



spongy bones, the abundant spongiform plexus already noticed. Nothing 

 is known of the iT/mjyJiaties of the nasal mucous membrane. The 

 nerves are, in the first place, branches of the fifth pair (ethmoidal, 

 posterior nasal, and a branch of the greater anterior dental nerve), which 

 supply especially the ciliated region of the organ, presenting there the 

 same conditions as the nerves in other sentient mucous membranes (of 

 the i^harynx, for example), but also extend to the proper olfactory 

 region ; and, as I noticed in one instance in the Calf, send scattered 

 dark-bordered primitive fibres in the course of the branches of the 

 olfactory nerves. The olfactory nerve, in its tract and hulh, contains 

 dark-bordered fibres and nerve-cells, of which we have already spoken. 



Fig. 313. — From the olfactory nerve of Man; magnified 350 diameters: A, nerve-tubes 

 from the traclus, in water; B, in syrup, appearing contracted ; C, nerve-cells, from the bulb; 

 Z>, nerve-fibres, from the brandies in the olfactory organ. 



