vi SYMPATHETIC SYSTEM 373 



the pelvic nerve contains upwards of 1000 afferent fibres, and after 

 cutting the sacral roots, Langloy ami Anderson found that only 

 about half a dozen of these fibres were not degenerated in the 

 nerve. Langley concludes that of the thousands of afferent nerve- 

 h'bres running from the viscera to the cord, not more than a dozen 

 or so have their trophic centres in the peripheral ganglia, these in 

 all probability being either post-gauglionic, medullated, or recurrent 

 afferent fibres. 



V. Having discussed the origin and course of the afferent and 

 efferent fibres of the sympathetic system, and acquired a general 

 idea of its structure, there remains the most important question of 

 all, the significance and functions of the sympathetic ganglia. 



Are we to regard these masses of ganglion cells as portions of 

 the cerebrospinal axis which have been displaced to the periphery, 

 but are still endowed with the functions of the centres ? The 

 earlier anatomists seemed to incline to this view when they gave 

 the name of cerebrum dbdominale to the solar ganglion. We have 

 learned that the fundamental property of the central nervous , 

 system lies in its capacity for subserving reflex acts, so in order to ! 

 decide this question we must ascertain whether the ganglia of the 

 sympathetic system are capable of subserving reflexes. 



From the above conclusions on the course of the afferent fibres 

 of the sympathetic, any such possibility must a priori be excluded, 

 seeing that all or nearly all the afferent paths run without inter- 

 ruption to the spinal ganglia, and never enter into direct relations 

 with the sympathetic ganglia. The excitations which they trans- 

 mit must therefore reach the centres of the cerebrospinal axis 

 before they can be reflected again to the periphery. 



This logical conclusion is apparently contradicted by a series 

 of observations which seem to show that under certain conditions 

 the spinal ganglia may function as true reflex centres. Cl. 

 Bernard (18G4) was the first to describe these phenomena. After 

 dividing the lingual nerve above the point at which it emerges 

 from the chorda tympani, and thus cutting off all connection with 

 the central nervous system, he artificially stimulated the peripheral 

 end of the lingual nerve, and saw an abundant secretion from the 

 submaxillary gland. We have already recorded the experiments 

 of Sokowin who observed that after cutting off all direct com- 

 munication with the spinal cord, stimulation of the central end 

 of the hypogastric nerve induces contraction of the bladder on 

 the opposite side. This observation, subsequently confirmed by 

 Nussbaum, Nawrocki and Skabitschewski, and others, was inter- 

 preted to imply that the inferior mesenteric ganglion was able to 

 function as a reflex centre. 



Other similar facts were observed in the sympathetic nervous 

 system by Langley and Anderson. They saw on repeating the 

 experiment of Sokowin that stimulation of the hypogastric also 



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