150 THE BRAIN AND ITS MENINGES. 



7, 7, the seventh pair, or auditory nerves ; being the second 

 nerves of a mixed character which have originated from the 

 base of the brain. This pair, however, are only motor and 

 special; and do not include the sentient, as did the fifth 

 pair. They consist of two distinct branches. The portio 

 mollis goes to the internal ear, for the special sense of 

 hearing ; the portio dura supplies the muscles of the face 

 with motion ; and hence is spoken of as the facial nerve. 



8, 8, a third nerve of mixed character, named the pneumo- 

 gastric, principally connecting the brain with the functions 

 of organic life, presided over by a distinct set of nerves, 

 called the sympathetic. It divides into three branches : — (1) 

 the glosso-pharyngeus, proceeding to the tongue and pha- 

 rynx; (2) the pneumogastric, distributed to the larynx, 

 thorax, and abdomen ; and (3) the spinal accessory (the 

 small nerve seen to join it coming from the spinal marrow), 

 which ramifies upon the neck ; 9, 9, the lingual, conferring 

 motion upon the tongue; 10, 10, those which are called 

 the tenth pair do not belong to the cranial nerves, but 

 really are the first spinal ; g, the medulla oblongata ; h, h, 

 the anterior lobes of the cerebrum ; i, i, the posterior lobes 

 of the cerebrum ; j, j, the small middle lobes of the cere- 

 brum ; k, k, the cerebellum. 



Fig 2. — The arteries of the hrain : 1, 1, the vertebrals ; 

 2, the inferior spinal, about to become a single vessel ; 3, 3, 

 the basilar, giving off" transverse branches on either side ; 

 4, 4, the posterior cerebellar ; 5, 5, the anterior cerebellar ; 

 6, 6, right and left communicating arteries, connecting the 

 basilar with the circulus arteriosis ; 7, the middle communi- 

 cating artery, connecting the basilar with the posterior trans- 

 verse artery ; 8, 8, internal carotids ; 9, 9, the ophthalmics ; 

 10, 10, the posterior cerebral ; 11,11, the middle cerebral ; 

 12, the anterior cerebral, dividing into, 13, 13, the right 

 and left anterior cerebral ; a, b, c, d, represents the circulus 

 arteriosis, or circle of Willis ; formed by the carotids, which 

 divide into, a, the posterior transverse ; &, the anterior 

 transverse ; c, the left lateral ; and d, the right lateral com- 

 municating arteries. 



THE BRAIN AND ITS MENINGES. 



At the head of the nervous system stands the soft white 

 and reddish mass contained within the cavity of the skull, 



