110 



THE NEBVOUS TISSUES 



accumulate in the vicinity of the nucleus. End fibrils of other 

 nerve cells have been demonstrated within the cytoplasm of the 

 nerve cell. Apathy has likewise demonstrated that fibrils occa- 

 sionally pass from one neurone to another, so that we no longer 

 consider that a neurone, though a structural unit, is in all cases 

 anatomically independent of all other neurones. The present 

 status of this much discussed question seems to be comparable to 

 that of the cell, as a histological unit of structure, which, though 

 formerly thought to exist independently of other cell units, has 

 since been found to be frequently connected, as by the intercellular 

 bridges of epithelium and of smooth muscle, the syncytial tissues, 

 etc. The neurones of the nervous system, therefore, while being 

 usually related to one another by contiguity or by contact only, 



FlG. 108. A NERVE CELL FROM THE TRAPEZOID NUCLEUS IN THE MIDBRAIN OF A 



RABBIT. 



a, neuraxis ; 6, neuraxes of other nerve cells which terminate in relation and appar- 

 ently fuse with the cytoplasm of the cell body ; c, points of fusion or zones of concres- 

 cence ; d, dendrites which have been cut off close to the cell body ; e, neuroglia. Iron 

 hematoxylin. Very highly magnified. (After Held.) 



may occasionally be more directly connected by fibrillge, which pass 

 from the processes of one neurone to the cell body or processes of 

 a second neurone (Apathy, Bethe), or by "concrescence," as de- 

 scribed by Held. 



The nerve cells are surrounded by a narrow interval which 



