486 GENERAL ANATOMY. 



centre, and by the other to the teguments, the organs of sense, 

 the muscles, and the vessels. 



771. The anatomists of the Italian school were sufficient- 

 ly well acquainted with all the pairs of nerves which are known 

 at the present time; but they did not class, number, or name 

 them as is now done. 



Willis gave them the numerical names and proper names 

 under which they have been generally known since his time, 

 viz. 



1st. The olfactory nerves; 

 2dly. The optic or visual nerves; 

 3dly. The motory nerves of the eyes; 

 4thly. The pathetic nerves of the eyes; 

 5thly. The fifth pair; 

 6thly. The sixth pair; 



7thly. The seventh pair, composed of a portio dura and 

 aportio mollis or auditory nerve; 



Sthly. The eighth, or the par vagum, with its spinal or 

 accessory nerve; 



9thly. The ninth pair, or the motory nerves of the tongue; 

 lOthly. The tenth pair, or the sub-occipital; 

 The nerves of the spinal marrow; 

 And the intercostal or sympathetic nerve. 

 Soemmering has modified the division of Willis. He esta- 

 blishes forty-three pairs of nerves, of which twelve pairs are 

 nerves of the brain: dividing the seventh pair of Willis into 

 seventh or facial, and into eighth or auditory; his eighth into 

 ninth or glosso-pharyngeal, into tenth or par vagum, and into 

 eleventh or accessory, the twelfth is the hypo-glossal; and re- 

 jecting the sub-occipital among the'spinal nerves, which are 

 then thirty pairs in number, the great sympathetic nerve 

 forms the forty-third pair. These modifications have been 

 generally adopted. 



Bichat divided the encephalic or cranial nerves, into those 

 of the brain, those of the protuberance, and those of the me- 

 dulla oblongata. This division is not founded upon exact ob- 

 servations. 

 The nerves may be exactly divided, 1st, into nerves with 



