REPORT ON THE PHYSIOLOGY OF THE NERVOUS SYSTEM. 83 



dyspnoea is much less considerable than when the wound is in- 

 flicted on the higher portion*. It was found, in all these trials, 

 that food introduced into the stomach after the operation re- 

 mained wholly undigested. Hence Dr. Philip infers the de- 

 pendence of secretion upon nervous influence, a conclusion, it 

 has been remarked by Dr. Alison, not logically deducible from 

 the experimental dataf. 



The par vagum cannot then, it is obvious, be included in the 

 class of nerves subservient solely to motion ; and it is even 

 doubtful whether the other two divisions of the eighth pair are 

 not also endowed with sensibility. Respecting the function of 

 the ninth, or lingvial, there is, however, no place for hesitation. 

 It has been experimentally proved by Mr. Mayo to supply the 

 muscles of the tongue ; though he also asserts that pinching it 

 with the forceps excited pain. Three of these nerves, the third, 

 sixth, and ninth, arise, it was first remarked by Sir Charles 

 Bell, from a tract of medullary matter continuous with the an- 

 terior column of the spinal marrow: and hence their exclusive 

 oflice of conducting motive impressions. 



II. There are thirty-two pairs of nerves of similar anatomical 

 origin and composition, which possess the twofold office of com- 

 municating motion and sensation. Of these, all excepting one 

 (the fifth pair of the cerebral nerves) spring from the spinal 

 marrow. These thirty-one pairs are precisely analogous in 

 formation, being all constituted of two distinct series of roots, 

 one from the anterior column, and one from the posterior column 

 of the spinal marrow. The posterior funiculi collected together 

 form a ganglion, seated just before this root is joined by the 

 anterior root. It has been already stated that the power of 

 propagating sensation resides in the posterior column, and in 

 the nervous roots arising from it, and that the motive faculty 

 has its seat in the anterior column and roots. The evidence, 

 also, supplied by Bell and Magendie, that the spinal nerves are 

 hence nerves of double office, has been fully detailed. It re- 

 mains, then, to establish the title of the fifth pair of cerebral 

 nerves to be included in the same class with the spinal nerves. 



The analogy in structure and mode of origin between the 

 fifth pair and the nerves of the spine has been long matter of 

 observation. Prochaska has thus distinctly noticed it in a pas- 

 sage of his Essay De Structurd Nervorum, published in 1779, 

 first pointed out to me by my friend Dr. Holme : " Quare 

 omnium cerebri nervorum, solum quintum par post ortum suum 



* Experimental Inquirt/, 3rd edit., p. 109. 



t Dr. Alison, Journal of Science, vol. ix. p. 106. 



g2 



