1 84 founial of Comparative Neurology and Psychology. 



and reaction to enable one to determine a boundary line between 

 them. 



As to the phyj^iological significance of the gemmules, their finer 

 structure and their reaction to anesthesia as well as the features of their 

 distribution as noted above, would seem to justify us in according to 

 them an important part in the maintenance of the conduction paths 

 within the central system. 



Goh^i 's Pericellular Net. 



The network of fine fibers which Gouii first described as sur- 

 rounding the nerve cells of the central and peripheral system has been 

 treated by subsequent writers as both nervous and non-nervous. The 

 more recent work, however, by Held, Bethe and others demonstrates 

 that this net is continuous with the terminals of medullated axones. 

 Hatai ('03) confirms this position and shows further that the fibrillae 

 of the net are of the same nature as those of the axone. That is to 

 say, they are a modified neurosomie reticulum. We have treated the 

 relation of the net to the nerve cell in the foregoing section upon the 

 gemmules. 



Hatai's observations would seem to be in harmony with Holm- 

 gren's ('99) views regarding the pericellular net of the spinal ganglion 

 cell of Lophiits. This net lies between the capsule and the cell and 

 between the lamellae of the capsule. It is continuous with fibers 

 which come from other regions of the spinal ganglion and with fibrils 

 which penetrate deeply into the cell. But these fibrils do not become 

 continuous with the protoplasm of the cell into which they penetrate. 

 A light. area always separates them from the sui-rounding protoplasm. 



Iiitraeelliihv Cainrliculi. 



In 1886 Frit.sch first discovered an intracellular system of ves- 

 sels in the nerve cell. His -observations were made upon certain 

 large cells in the medulla of Lophiiis. He interpreted the structures 

 as genuinely vascular. Holmgren ('99) discovers similar structures 

 in the spinal ganglion cell of Lophiiis and claims that he is first to con- 

 firm the observations of Fritsch. But during the same year of 

 Holmgren's publication Nelis ('99) introduces "un nouveau detail" 

 in the protoplasmic structure of the nerve cell, which has many fea- 

 tures in common with the intracellular vessels of Fritsch and Holm- 

 (}ren. These structures, the "Gefasse" of Fritsch. the "Kanal- 

 chen" of Holmgren and "I'etat spiremateux" of Nelis, we shall for 

 convenience designate as intracellular canaliculi. 



