CHAPTER X. 



DISEASES OF THE NERVOUS SYSTEM. 



GENERAL REMARKS ON THE STRUCTURE AND 

 FUNCTIONS OF THE NERVOUS SYSTEM, AND 

 ON THE LOCALIZATION OF NERVOUS DISEASES. 



We do not purpose here to enter into the anatomy and 

 histology of the nervous system, but to cursorily review 

 some general points which are of especial importance in the 

 study and in the localization of the diseases of the nervous 

 system. 



The nervous system is made up of two ultimate factors, 

 nerve-fibres and nerve-cells, and these are intimately asso- 

 ciated together. 



The white matter of the brain and of the spinal cord is 

 composed of nerve-fibres imbedded in a ground substance, 

 or neuroglia. The grey matter of the brain and spinal cord 

 is made up of nerve-fibres and of nerve-cells, or ' ganglion 

 cells,' as they are termed, similarly imbedded in the 

 neuroglia. 



The neuroglia itself consists of three different kinds of 

 elements — (1) a homogeneous, transparent, semi-fluid matrix^ 

 which in hardened sections appears more or less granular ; 

 (2) a network of very delicate fibrils, ' neuroglia fibrils^ which 

 resemble elastic fibres ; (3) small branched nucleated cells 



