Herrick-Coghill, Nave Endings in the Skin. 47 



DogieP has shown that in the eyelids of man, for example, 

 where the number and complexity of the sense organs is ex- 

 treme, the terminal bodies consist of a covering of several con- 

 nective tissue layers separated by zones of flat epithelial cells 

 enclosing the nerve net. The nerve net is described as lying 

 free in the interior of the bulb, though a faintly stained material 

 was noticed and regarded as coagulated lymph which may rep- 

 resent cellular elements not competent to be revealed by the 

 methylene blue method. (Fig. 9.) The nerve fiber loses its 

 sheath before it penetrates the bulb and at once divides into 

 spirals or coils forming a loose mesh-work. Aside from these 

 specific cells, there are extensive arborizations and nets of fibers 

 diffusely scattered in the epithelium at large. 



In some respects the fullest description of the highly differ- 

 entiated sense organs of the skin of the genitalia has been given 

 by Dogiel and his results are pertinent to our purpose, inasmuch 

 as he finds that all the end-organs reduce to one type — a term- 

 inal recticulum. The so-called genital sense organs and the 

 Krause's and Meissner's bodies all prove to consist of a capsule 

 containing a reticulum of varicose fibers and, especially in the 

 case of the genital corpuscles, those of the same order are fre- 

 quently connected by lateral anastomoses. In addition to these 

 special organs, Dogiel traces meduUated fibers into an inter-cel- 

 lular reticulum within the epithelium so fine and dense as to 

 come apparently into relations with all the cells of the deeper 

 parts of this layer. Occasionally a branch turns peripherally 

 and ends in a knob at some distance- below the surface. We 

 seem, then, to have evidence that the typical form of nerve 

 ending is a close pericellular network, though Dogiel's method 

 is not such as to allow of determining the relation of the fibers 

 to the cells. (Fig. i.) 



The most remarkable suggestion respecting the homologies 

 of the sense organs of the skin in amphibians is that of Maurer 

 who thinks that the hair of vertebrates can be traced back phy- 



' A. S. Dogiel. Die Nervenendigungen i. Lidrande, etc. Archiv f. Mik. 

 Anatomic, XLIV, i, 1894. 



