THE NERVE CELL 



127 



directly connected by fibrillse, which pass from the processes of one 

 neuron to the cell body or processes of a second neuron (Apathy, Bethe), 

 or by 'concrescence/ as described by Held. 



The nerve cells are surrounded by a narrow interval which separates 

 them from the surrounding tissue. This is presumably a lymphatic or 

 tissue fluid space. Holmgren has demonstrated also the presence, within 

 the cytoplasm of the nerve cell, of minute canaliculi which form an intra- 



FIG. 140. A NERVE CELL FROM THE TRAPEZOID NUCLEUS IN THE MIDBRAIN OF A 



RABBIT. 



a, axon; 6, axons of other nerve cells which terminate in relation and apparently 

 fuse with the cytoplasm of the ceil body; c, points of fusion or zones of concrescence; 

 d, dendrons which have been cut off close to the cell body; e, neuroglia. The cyto- 

 plasm shows a neurofibrillar network and Nissl granules. Iron hematoxylin. Very 

 highly magnified. (After Held.) 



cellular network, more abundant near the surface of the cell, and which 

 he has termed juice canaliculi, or trophospongium. These canaliculi 

 may possibly account for the peculiar mtracellular network which Golgi 

 has demonstrated in the periphery of the nerve cell, by a modification of 

 his rapid silver impregnation method. 



The processes of the nerve cell are of two varieties: the one, broad, 

 granular, and rapidly dividing in the vicinity of the cell body into a 

 number of branching subdivisions, is the dendron; the other, long, slen- 

 der, and finely but distinctly fibrillar, arises from the cell body direct, or 



