584 THE POSTERIOR PITUITARY AND THE NERVOUS SYSTEM. 



a net-work of fibrils which receives impulses from the poste- 

 rior pituitary body? There is no evidence available to suggest 

 that such is the case, and the functional relationship with the 

 latter through the vasomotor supply of the pial vessels is the 

 only link between the two organs that existing data permit us 

 to accept. If, therefore, a regulative mechanism exists, it must 

 be one connected with the vascular system, and so disposed as 

 to enable it to govern the circulation through one or more 

 neurons simultaneously. It must supply its own nervous en- 

 ergy, for we have seen that Andriezen found the vasomotor 

 nerves to distinctly terminate upon the muscular coats of the 



"A PROTOPLASMIC NEUROGLIA-CELL FROM THE HUMAN BRAIN 

 (FOURTH LAYER OF CORTEX) SHOWING Two EXPANDED CONICAL 

 DISK-LIKE ATTACHMENTS TO A VESSEL." (Andriezen.) 



pial vessels; indeed, it must be as autonomous an organ as is 

 the neuron itself. 



Such an organ we have, it seems to us, in the neuroglia- 

 cell shown in the above illustration, which Andriezen has named 

 the "protoplasmic neuroglia-cell," and describes as follows 58 : 

 "The protoplasmic glia-cell has a distinct cell-body, which is 

 irregularly oval, frequently pyriform. Its various protoplasmic 

 processes are of moderate length, they exhibit great variations 

 of caliber, some being stout and coarse and others exceedingly 

 fine. These processes are also dendritic: a thing never seen 

 in the stellate cells. A most striking feature is the shaggy 



"Andriezen: British Medical Journal, July, 1893. 



