FUNDAMENTAL "LAWS" OF NERVE-ACTION. 191 



Section. 



At (1) 



At (2) 



At (3) 



At (4) 



At (5) 



Channel. 



Afferent fibres of No 

 posterior root. 



Afferent fibres of the 

 cerebellar tract. 



Efferent fibres of the 

 pyramidal tract. 



Above Section. 



degeneration; con- 

 tinuity of fibres with 

 ganglion cells of pos- 

 terior root. 



Below Section. 



Degeneration, reaching 

 to periphery. 



Afferent fibres oflDegeneration, reaching No degeneration; con- 

 posterior root and 

 of Coil's column. 



to spinal grey matter 

 (Clarke's column, 

 Burdach's nucleus). 



Degeneration, reaching 

 to cerebellum. 



Efferent fibres 

 anterior root. 



No degeneration ; con- 

 tinuity of fibres with 

 cells of Rolandic 



area. 



of'No degeneration ; con- 

 tinuity of fibres with 

 cells of anterior cor- 

 nua. 



tinuity of fibres with 

 ganglion cells of pos- 

 terior root. 



No degeneration; con- 

 tinuity of fibres with 

 cells of Clarke's 

 column. 



Degeneration, reaching 

 to cells of anterior 



cornua. 



Degeneration, reaching 

 to periphery. 



regarding the trophic and functional relations of its principal 

 cells and cell-connections, and to illustrate (a) the law of 

 trophic action, (ft) the law of forward direction, in conformity 

 with modern histological views. 



The law of trophic action is to the effect that the nutrition 

 of nerve-fibres is dependent upon their protoplasmic con- 

 nection with nerve-cells, and is established upon the follow- 

 ing- data. 



Sections 1, 2, 3, 4, 5 produced effects, the situation and 

 extent of which are indicated by the blackened tracts. 



The law of forward direction is to the effect that func- 

 tional impulses pass in the direction of the arrows from I. 

 to VII., and in that direction only. 



No attempt has been made to represent " collateral " 

 connections. Communication between III. and VI., and 

 between IV. and V., the existence of which we are forced 

 to infer from physiological consideration, is indicated by 

 dotted lines. 



The cells and pericellular networks pointed out by 



