Prentiss, Peripheral Networks. gj 



lated fiber-bundles over the whole inner surface of the palate. 

 From this plexus fibers pass off to the epithelium. According 

 to Bethe each medullated fiber divides into four branches and 

 each branch innervates a different sensory organ, the number 

 for each organ being but two. This peculiar and definite 

 method of innervation, he points out, is the most natural ar- 

 rangement by which each end organ may receive a distinct 

 nerve supply at the expense of the smallest number of nerve 

 fibers — a separate nerve supply for each sensory organ being 

 requisite for the localization of tactile stimuli. 



My preparations confirm the general conclusions of Bethe, 

 but the distribution of the sensory fibers is not as simple as he 

 supposed. It is true that usually only two or three large fibers 

 innervate each sensory organ ; these break up into numerous 

 fine fibrils, which, after a tortuous course, end between the epi- 

 thelial cells. The sensory organs in which these fibers end 

 project slightly above the surface of the palate and are most 

 numerous at the sides. Bethe counted an average of 210 end 

 organs but only 70 fibers in the palatine nerve; if each fiber 

 branches into four, as Bethe asserts, this would allow an aver- 

 age of between two and three branches for each sensory spot. 

 But in addition to these branches I find numerous bundles of 

 fibrillae given off from each medullated fiber. These divide 

 into still smaller fibrils which form a network of fine neuro- 

 fibrillae and probably connect the different sensory organs. This 

 network has not to my knowledge been observed in the integu- 

 ment of the frog, but Sfameni (:02) and Ruffini (:01) have 

 recently described structures apparently identical to it in the 

 skin of man. In the frog the fibrillae composing the network 

 are very difficult of demonstration. In the great majority of 

 methylene blue preparations they are but incompletely stained, 

 and of good preparations I obtained but two or three out of 

 perhaps a hundred trials. The network lies directly beneath 

 the epithelium and is composed entirely of non-medullated fibril- 

 lae (Fig. 2). Strands of these are given off from the medullated 

 fibers as seen in the figure at a and a'. The strands divide and 

 their fibrils are apparently continuous with each other in a fine- 



