THE NERVOUS TISSUES. 



these processes, when compared with the richly-divided protoplasmic, 

 may be regarded as unbranched, the existence of delicate lateral off- 

 shoots, or collateral fibrils, has been established ; these delicate 

 branches pass backward towards the gray matter, within which 

 they end, often at considerable distances, in relation with other 

 cells. 



FIG. 83. 



Nerve-cell from the spinal cord, isolated by maceration and teasing ; the numerous branched pro- 

 toplasmic processes are somewhat displaced and distorted, owing to manipulation : a, axis-cylinder 

 process. 



Nerve-cells of the second type are distinguished by the be- 

 havior of the axis-cylinder process ; this, instead of passing into 

 the white matter to become the centre of a nerve-fibre, never leaves 

 the gray matter in which the ganglion-cell lies, but, after a longer 

 or shorter course, rapidly undergoes division and subdivision in the 

 production of a terminal arborization of delicate fibrillae ; these 

 ramifications are limited entirely to the gray matter, their exact 

 manner of ending and their relations to other cells varying in dif- 

 ferent parts. The free division of the axis-cylinder process does 

 not curtail the branching of the protoplasmic extensions, which are 

 often very conspicuous, notwithstanding the numerous bifurcations 

 of the former. In some instances the axis-cylinder processes of 

 cells of this type split up into fibrils which enclose the bodies of 

 other nerve-cells within basket-like net-works; a notable ex- 

 ample of this arrangement exists in the cerebellum around the cells 

 of Purkinje. 









