102 J. GORDON WILSON 



The literature of the nerve distribution in this structure in 

 mammals is by no means voluminous. In addition to the work 

 quoted above, it is contained in papers by Kessel, Jacques, Cala- 

 mida and Deinike. Of these the only author who has described 

 the nerves in the membrane of man is Kessel. Jacques' work was 

 done in the membrane of the cat and dog; Calamida's investi- 

 gations were carried out on several of the lower animals — horse, 

 cat, goat, etc.; Deinike limited his work to the ox and horse. 

 The papers of Jacques, Calamida and Deinike are not here re- 

 viewed as they do not bear directly on the nerves in man and 

 further since this has been done sufficiently in a former paper. 

 Within the last year an article has appeared by Gemelli on the 

 nerves in the cat, horse, dog and ape. 



Kessel found that in man the principal nerve, composed of 

 medullated fibers, passes from the external auditory meatus, on 

 to the membrane at the upper part of the posterior segment close 

 to and behind the artery. In the onward course of the nerve 

 branches are given off which accompany the vascular twigs. 

 Corresponding to the forking of the artery over the manubrium 

 the nerve divides into two branches of which one supplies the an- 

 terior, the other the posterior and lower part of the manubrium. 

 Besides the main trunk several smaller nerves, accompanying 

 blood vessels, pass to the membrane from various parts of the 

 periphery. All these nerves in their course give ofT branches 

 which lie between the cutis and membrana propria forming what 

 he calls the ground plexus. Fibers also enter the membrana 

 tympani from the plexus tympanicus; these fibers reinforce the 

 nerve supply which reaches the mucous membrane from the 

 cuticular side. The ultimate distribution of these nerves is to be 

 found : 



(a) around the capillaries — forming a capillary plexus, 



(b) under the stratum Malpighii — forming a subepithelial 

 plexus, 



(c) under the mucous membrane — forming a submucous plexus. 

 As a result of staining with chloride of gold he describes 



(d) in the course of the capillaries single nerve fibers consisting 

 of axis cylinders in which are nodal swellings, containing a nucleus, 



