SIR CHARLES BELL'S DIVISION OF NERVES. 89 



of filaments destined for both motion and sensibility; that the ence- 

 phalic nerves, which have but one root, are destined for one of these 

 exclusively, and that they are either nerves of motion, or of sensation, 

 according as their roots arise from the anterior or the posterior tract 

 of the medulla. 



It has already been remarked, that the medulla oblongata, according 

 to some anatomists, is composed of three fasciculi or columns on each 

 side ; an anterior, a middle, and a posterior; and it has been affirmed 

 by Sir Charles Bell, that whilst the anterior column gives origin to 

 nerves of motion ; and the posterior to nerves of sensibility; the middle 

 gives rise to a third order, having the function of presiding over the 

 respiratory movements ; and which Sir Charles, accordingly, calls respi- 

 ratory nerves. To this third order belong, the accessory nerve of 

 Willis or superior respiratory ; the vagus; the glosso-pharyngeal; the 

 facial, called by him the respiratory nerve of the face; the phrenic; 

 and another having the same origin the external respiratory. Sir 

 Charles's views, if admitted, lead, consequently, to the belief, that there 

 are at least three sets of nerves, one destined for sensation; another 

 for motion ; and a third for a particular kind of motion the respira- 

 tory; and that every nerve of motion communicates to the muscles, to 

 which it is distributed, the power of aiding, or taking part in, motions 

 of one kind or another ; so that a muscle maybe paralyzed, as regards 

 certain movements, by the section of one nerve, and yet be capable of 

 others of a different kind, by means of the nerves that are uninjured. 

 The accompanying plate exhibits the system of respiratory nerves, as 

 given by Mr. Shaw, 1 son-in-law of Sir Charles Bell, who was prema- 

 turely snatched from existence, after having made numerous useful 

 contributions to medical and surgical science. 



A, the cerebrum, B, the cerebellum, C C 8. Branches of the glosso-pharyngeal. 

 C, the spinal marrow, D, the tongue, E, the 9. Lingualis, sending branches to the tongue, 



larynx, F, the lungs, G, the heart, H, the sto- and to the muscles on the fore part of the 



mach, I, the diaphragm. larynx. 



111. Par vagum, arising by a single set of 10. Origins of the superior external respira- 



roots and passing to the larynx, lungs, heart, tory or spinal accessory. 

 and stomach. 11. Branches of the last nerve proceeding 



2. Superior laryngeal branches of the par to the muscles of the shoulder. 



vagum. 12 12 12. Internal respiratory or phrenic 



3. Recurrent or inferior laryngeal branches passing to the diaphragm. 



of the par vagum. The origins of this nerve are seen to be 



4. Pulmonic plexus of the par vagum. much higher than they are generally de- 



5. Cardiac plexus of the par vagum. scribed. . 



6. Gastric, plexus of the par vagum. 13. Inferior external respiratory, to the mus- 



7. Respiratory nerve or portio dura passing cles on the side of the chest. 

 to the muscles of the face, arising by a series 



of single roots. 



Yet this division is by no means universally admitted ; and even by 

 some who are of opinion, that the sensitive and motor filaments arise 

 from distinct tracts of the spinal cord, it is denied that this is the case 

 with those that originate from the upper part of the cord; there being 

 in the medulla oblongata a blending of the sensitive and motor tracts 

 which cannot easily be explained. Pathological cases, too, occasionally 



1 Manual of Anatomy, &c., 3d edit., Lond., 1822. Reprinted in this country. 



