54 'Journal of Comparative Neurology and Psychology. 



distinct zones in the plasma of the cell. Small canals are scattered throughout 

 the cytoplasm, no region being free from them. They do exist in the nucleus 

 (Fig- 3)- The canals may or may not occur in the protoplasmic processes of the 

 cell. The canals run about the NisSL flakes, sometimes passing through them, 

 at other times merely surrounding the flakes, or they may be free in the cytoplasm. 

 Some of the small canals approach the nuclear membrane, but in no place were 

 they seen to penetrate it. The size and extent of the canals is dependent on the 

 physiological state of the cell. The canals do not have a distinct wall but a linear 

 boundary due to the arrangement of the cytoplasmic granules. The intracellular 

 lymph canals of the central ganglion cells open into channel-like spaces. 



i^t^k.. 



Fig. 



Fig. 4. 



Fig. 3. Ganglion cell of white rat. Illustrates penetration of cytoplasm and nucleus of nerve cell by 

 sap canals. The isolated clear spaces are the cut ends of sap canals. After Pewsner-Neufeld ('03, 

 Fig. 3)- 



Fig. 4. A large ganglion cell with tubes formed from the capsule extending entirely through it. After 

 Bethe ('00, Fig. 2). 



Studnicka ('99) presents a discussion of the origin and use of the canals in 

 ganglion cells. The little canals can very often be followed in the body of the cell 

 some distance, indeed, often through the half of the entire cross section of the cell. 

 They are seen in such a study to branch freely. These little canals which are iden- 

 tical with those described by Holmgren, arise very likely through the union of a 

 row of vacuoles. Many of the canals have smooth outside walls. Some separate 

 vacuoles are found which are explained as being the cross sections of the branches 

 of such vacuoles as have not yet fused into canals. He is unable to define the con- 

 tents of the canals and alveoli, but suggests that they are during life, no doubt 

 filled with a fluid which may be identical with that in the pericellular space with 

 which the little canals are united. Some of the greater alveoli contain a homo- 

 geneous substance which colors more intensely with eosin and is to be considered 

 a special deposit. 



