STRUCTURE OF NERVE-CELLS. 



319 



be cells, the processes of which have become broken away during the manipulation 

 required for isolation. 



Fig. 369. A NERVE-CELL FROM THE CEREBRAL CORTEX (Qolgi). 



a, axis-cylinder process. 



Fig. 370. A BIPOLAR NERVE-CELL, WITH ITS POLES PROLONGED INTO MEDULLATED 



NERVE-FIBRES (Key and Retzius). 

 The whole is invested by the primitive sheath. S, J?, nodes of Ranvier. 



It has been shown that many cells have at least one of their processes prolonged 

 as a nerve-fibre (axis-cylinder process) and the statement is probably true of [all 



