SIR CHARLES BELL. 27$ 



distinctly traced. Both nerves arise in the medulla 

 oblongata, at a point which has been denominated the 

 "vital knot," and the filaments of both preside over 

 respiration. A division of either of these nerves re- 

 sults in partial or complete asphyxia. Bell called 

 these mixed functions " excito-motory," to denote 

 the distinctive character and reciprocal relations of 

 the respiratory functions. 



To the discoveries of Bell should be accredited 

 the origin of sensory nerves in the gray matter of the 

 cerebrum, of the medulla oblongata, and of the spinal 

 cord ; and the origin of motor nerves in white neurine. 

 Bell ascertained that the " spinal accessory " nerve wa^ 

 motor in function, but did not announce that the pneu- 

 mogastric derived all of its moving energy from that 

 source. It required the experiments of Bischoff and 

 Bernard to complete the discovery. 



The sympathetic system of nerves was first made 

 understandable by the investigations of Sir Charles 

 Bell. Many years previously, John Hunter had delved 

 in this field, and gained creditable headway, but had 

 not made those nice distinctions in regard to the spe- 

 cial functions of a nerve that were the forte of his 

 successor. Hunter studied the ganglionic and visceral 

 nerves in worms and the articulata generally, and saw 

 motion and sensation manifested by the same bundles 

 of nerves. Bell conjectured that the leading office of 

 these parallel chains of knotted cords embraced func- 

 tions in addition to those of locomotion and sensation, 

 for he found them displayed along the viscera of the 

 body, as if to exercise an influence over digestion, as- 

 similation, and secretion. And he found, too, that 

 sympathetic filaments inosculated with motor and 

 sensory filaments coming from the cerebro-spinal sys- 



