564 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



vessels" (Berdal). This recalls the interesting feature in Fig. 

 3 of the plate opposite page 550. In the projection-cell repre- 

 sented the extremity of the long and irregularly-swollen apical 

 process is also connected with the wall of what must be a 

 diminutive blood-channel, if plasma is at all the cause of the 

 cellular engorgement. Again, the neuroglia-cell, shown below, 

 copied from an article by Andriezen, to which we will presently 

 refer, 61 may be seen to be directly attached to a vessel. Indeed, 

 we have Golgf s own testimony to the effect that some of the 

 protoplasmic extensions of the nerve-cell are attached to neu- 

 roglia-fibers and to blood-vessels. 



Pio. 1. "A PROTOPLASMIC GLIA-CEL.L FROM A HUMAN BRAIN 

 (FIRST LATER OF CORTEX)." (Andriezen.) 



The manner in which the neuroglia-cells and their fibers 

 are connected with blood-vessels suggests that they are essen- 

 tially different structurally, the neuroglia-elements being, not 

 branches or subdivisions of the vascular system, but nervous 

 structures which, at a given time during embryological devel- 

 opment, became affixed to the vascular walls. This is sustained 

 by the fact that neuroglia is, like all nervous elements, of epi- 

 blastic origin. Again, there is considerable analogy between 

 nerve- and neuroglia- fibers. Foster emphasizes this fact when 



"i Andriezen: Brain, Winter, 1894. 





