496 COMPARATIVE PHYSIOLOGY. 



by such connections ; and that, apart from the multiplicity of 

 cells with different functions to perform, situated in different 



Fig. 356.— Diagrammatic representation of the coarse of some of the fibers in the cere- 

 brum of man (after Le Bon). 



areas, the complexity and at the same time the unity of the 

 encephalon becomes increasingly evident, merely upon anatomi- 

 cal grounds ; but we shall find such a view still further strength- 

 ened by study of the functions of the various parts. While the 

 tracts enumerated are anatomical and have been clearly traced, 

 there can be little doubt that many others yet remain to be 

 marked out; and that, apart from such collections of fibers, we 

 must recognize functional paths by the neuroglia, and possibly 

 others still. It is not to be forgotten that in the brain, as in the 

 spinal cord, nerve-cells are themselves conductors, and while 



