ioo Journal of Comparative Neurology. 



head as the seat of intelHgence and perception. With slow 

 gradations the apparent fantastic and irregular form of the 

 wrinkled brain surface has been systematized into a general 

 ground-plan. Segments have been differentiated and a fissural 

 pattern for the cerebrum has been formulated. Deeper than the 

 surface, however, there is encountered a bewildering maze of 

 cells and fibers, the intricate arrangement and complex relations 

 of which have at the present time, only begun to be under- 

 stood. 



In the achievement of a great discovery, many are prone to 

 overlook the factors by means of which it is made possible. The 

 discovery of a new planet very justly brings great renown to 

 the discoverer, — we usually stop at that and take no cognizance 

 of the wonderful mechanism of the telescope, the laws of astron- 

 my, and other accessories that co-operate in the grand result. 

 And so it has been with our knowledge of the structure of the 

 nervous system, great as it is today but at the same time inade- 

 quate. The results of the last ten years which have so com- 

 pletely revolutionized our conceptions of the nerve elements 

 were possible only through improvements in microscopical ap- 

 paratus and technique, and the improvement of histological 

 methods. With the additional knowledge gained from the new 

 methods, there must of necessity occur change in the termin- 

 ology. The old notion of a nerve cell (justified by the old 

 methods) that it consisted merely of a cell body with its en- 

 closed nucleus and nucleolus is no longer tenable. Important 

 as are these parts to the nutrition and activity of the cell, no 

 less important to the full attainment of its function is the pres- 

 ence of its various appendages. 



The Golgi-Cajal method is too well known to require any 

 description. The formation of a silver-bichromate deposit in or 

 upon the nerve cell and its processes has furnished us with pic- 

 tures of these elements, which for beauty and clearness of out- 

 line surpass anything that has preceded it. The results furnish 

 us with at least a workable hypothesis regarding nervous phe- 

 nomena which before was merely conjecture. 



This method has shown, and accumulated evidence seems 



