Prentiss, PciipJieral Netivorks. ill 



branches supplying the palate. Furthermore the endings of 

 the medullated fibers in th6 sensory spots of the epithelium 

 were not demonstrated, endings which, under normal con- 

 ditions, are almost always stained. 



It is clear from such preparations that isolation from the 

 central nervous system was completely accomplished by the 

 operation. For the medullated fibers of the palatine nerves 

 were not only wholly degenerated, but also stimulation of the iso- 

 lated region failed to call forth any response. According to 

 Bethe the myelin substance does not begin to undergo degen- 

 eration until some time after the axis cylinders have lost their 

 staining properties, and it follows that the latter have been de- 

 generate for a considerable period. But is this the case with 

 the non-medullated fibers of the peripheral networks which 

 Bethe and others have asserted to be directly connected with 

 true nerve cells? 



In every degeneration preparation of the palate methylene 

 blue failed to stain the fine network of the sensory fibrillae 

 which I have described and shown in figure 2. This result was 

 to be expected, as the network consists only of non-medullated 

 fibrillae, all branches of medullated fibers, and goes to show that 

 the degeneration of the latter is complete. But in both cases in 

 which the palatine nerves had been isolated for five weeks the 

 subepithelial and perivascular networks were beautifully stained. 

 Neither fibers nor cells showed the least trace of degenerative 

 changes. In regions where the stain was well differentiated 

 the neurofibrillae could be easily made out, proving that these 

 elements were in a normal condition, and that the staining of 

 the fibers was not alone due to the impregnation of the peri- 

 fibrillar substance. 



A portion of the subepithelium network from one oftheprep- 

 ations oi series j is shown in figure ii. It will be noted that 

 a number of cells are grouped together at the points a and a' . The 

 spot where such a group of cells occurs is in every case im- 

 mediately beneath a sensory organ, and the fibers radiate out 

 from these regions. Certain fibrils pass from the cells and 

 apparently end in the sensory organs. I was not able to settle 



