Prentiss. Pcripho'al Networks. 



103 



the sensory spots, and end freely in the epithelium. I have 

 never observed fibers from this network innervating the capil- 

 laries, but such may be the case. It is, however, connected 

 with the perivascular plexus ; meduUated fibers also frequently 

 unite with it as may be seen in figure 5. The true nature of these 

 structures has been called into question by many neurologists ; I 

 may state here that when I first saw them in my preparations I did 

 not believe that they were nervous structures. After studying 

 them carefully, however. I gathered the following evidence: (i) 

 specific stains for elastic fibers and connective tissue do not 

 demonstrate these networks ; (2) as already observed, the fibers 

 of the networks are continuous with branches from medullated 

 fibers ; (3) neurofibrillae may be distinctly observed in well dif- 

 ferentiated preparations of these networks and the fibers have 

 the varicose appearance characteristic of nerves. In the face of 



Fig. 6. A group of three cells from the subepithelial nerve network, show- 

 ing the course of the neurofibrillae, and the connection of a large fibril with a 

 medullated fiber; the fibril branches close to the first nucleus, but no network is 

 formed in any of the cells by the neurofibrillae. X 700. 



these facts there can be no doubt that the fibers of both the 

 perivascular and subepithelial networks are nerve fibers. As to 

 the nature of their cells, the histological evidence is no means 

 conclusive. My preparations of the frog's palate do not sustain 

 the observations of Bethe (:03) as to the presence of a neuro. 



