392 Journal of Comparative Neurology. 



viewed from the surface, presents an intermingled and confused 

 mass of nerves, medullated and non-medullated, with their telo- 

 dendria, in which it is impossible to trace any single fiber 

 through all its branchings to its terminations and so view in a 

 connected and orderly way the relations of the several parts to 

 each other. Occasionally however, a preparation may be ob- 

 tained in which, in a given area, few or perhaps only one fiber 

 is stained with the methylene blue and this one very perfectly 

 to its minutest branches. In this case, we may observe over 

 how large an area a single nerve is distributed. PI. XXVI, Fig. 

 5, represents such a fiber with its terminal branching. As this 

 is taken from a rather thick, tangential or somwhat oblique 

 section of the mucosa, however, and not from a surface prepar- 

 ation, there is no doubt that many of the terminal branches 

 with their telodendria have been removed and that the ending, 

 if complete, would occupy a much larger area. This has been 

 demonstrated in surface preparations, in some of which the 

 medullated and non-medullated nerves have been traced through 

 much more complicated branching and dividing than that shown 

 in the figure. The end-branches of these nerves intertwine 

 and overlap in such a way that a surface view of the mucosa 

 with the surface of the epithelium in focus shows an almost uni- 

 form distribution of the telodendria in most of the epithelium. 

 When we compare the small number of the large, medul- 

 lated, sensory fibers found in the nerve trunks of the oesopha- 

 geal plexuses with the large number of non-medullated nerves 

 taking part in the free sensory ending in the epithelium, we are 

 convinced that each nerve divides repeatedly and covers with 

 its branches a relatively large area. Similar free sensory nerve 

 endings have been found in the ducts of the salivary glands by 

 Arnstein (2) and Huber (23), in the respiratory tract by Plo- 

 schko (35), Berkley (2a) and Smirnow (39), in the endo- and 

 peri-cardium by Smirnow (40) and Dogiel (13) and in the blad- 

 der by Ehrlich (16), Cuccatti (8), Grunstein (19) and Huber 

 (24). The latter has described and figured, from the mucosa 

 of the urethra of a cat, a free sensory ending in which twenty 

 medullated nerve fibers arising from a single nerve fiber could 



