Prentiss, PeripJicral Netzvorks. 99 



meshed irregular network ; for under a high magnification some 

 of the meshes were found to be formed of a single fibrilla, and 

 it is absolutely impossible to say where one fiber ends and an- 

 other begins. Certain fibrils from this network end in the sen- 

 sory spots of the epithelium (Fig. 2, b, b') ; others terminate 

 freely in the regions between the sensory organs. There 

 is thus a diffuse sensory nerve supply throughout the epithelium 

 of the palate. 



From certain preparations in which the fibrils of this net- 

 work were incompletely stained, I was able to trace a single 

 fibrilla from one medullated fiber into another without loss of 

 continuity (Fig. 3). This connecting fibril appears to be homo- 

 geneous in structure throughout its entire length. It is very 

 possible that such a condition may be produced by the over- 

 lapping of two fibrils. I myself have concluded after a careful 

 study of these networks that they are formed by such an over- 

 lapping of two fibrils and not by the direct union of fibrils from 

 different "neurones." In either case it is impossible to say 

 that the fibril belongs to one neurone or to the other. 



The presence of fibrillar networks throughout the integu- 

 ment is what we should expect from the physiological facts as 

 to tactile sensations. The whole surface of the skin is more or 

 less sensitive to tactile stimuli but the localization and acuteness 

 of the sensations depend upon the presence of special recep- 

 tive organs. If two stimuli are applied to a region between 

 sensory spots only one sensation is felt, as the stimulus is dif- 

 fused and affects equally a number of neurones. If, however, 

 the two stimuli are so far apart as to affect different sensory 

 spots, innervated by distinct nerve fibers, each of these will be 

 strongly stimulated, and two distinct sensations will be the 

 result. 



Fig, 2. A subepithelial network of neurofibrillae from the palate of the 

 frog; a, a\ strands of fibrillae from medullated fibers; b, F, fibrillae 

 which apparently end in the sensory spots; c, c' , two sensory spots. 

 The network is viewed from the epithelial side of the palate, and the termina- 

 tions of the sensory fibrils among the cells of the epithelium are indicated by 

 knob-like enlargements. X 330; details with Leitz 1-12 oil immersion. 



