NEUROLOGY. 127 



cast of the bead of Napoleon ; fig. 4, that of Tiedge ; fig. 5, of Kant ; fig. 6, 

 of Talleyrand ; fig. 7 represents the skull of Schiller; fig. 8, that of a Green- 

 lander ; fig. 9, that of a suicide ; fig. 10, that of a poisoner ; fig. 11, that of 

 a Cretin ; fig. 12, that of an idiot ; fig. 13, that of a brown sajou ape ; fig. 

 14, that of a Grrison ape. 



4. Anatomy of the Nerves. 



A. Cerebral Nerves. 



1. Olfactory Nerves. First Pair. This pair of nerves is the first 

 given off, arising from the inferior anterior surface of the brain. From the 

 bulb which each of these nerves forms at the side of the crista galli, several 

 branches descend into the nose through the foramina in the cribriform plate ; 

 they may be divided into the internal, middle, and external. The internal 

 hranches, about ten in number, descend in grooves along the septum, and 

 subdivide into many filaments, which form a plexus with each other in the 

 mucous membrane. The vuddle branches are distributed to the mucous 

 membrane lining- the roof of each nostril. The external branches descend 

 along the groove, on the turbinated bones, dividing and communicating 

 frequently with each other, so as to form numerous plexuses which are lost 

 in the pituitary membrane. 



2. Optic Nerves. Second Pair. This arises by a broad flattened root, 

 one portion of which comes from the thalamus opticus, and another from 

 the testis ; advancing it adheres so closely to its fellow, that the two seem 

 fused together, in such a way that there is no line of separation between 

 them. This junction presents the form of the letter X, and is called the 

 cbiasma. Separating again after this union, each nerve passes through its 

 optic foramen, and piercing the sclerotic and choroid membranes of the eye, 

 expands to form the retina. This nerve is accompanied by the ophthalmic 

 artery. • The other nerves distributed to the eye are, the third nerve, the 

 fourth, the ophthalmic branch of the fifth, and the sixth. 



8. The Motores Oculi. Third Pair. This arises from the internal face 

 of the crus cerebri, in advance of the anterior margin of the tuber annulare. 

 After passing through the foramen lacerum orbitale, it divides into two 

 branches, a superior and an inferior. The superior or smaller passing above 

 the optic and nasal nerves, divides into two branches, one to the superior 

 rectus, the other to the levator palpebrse. The inferior or the larger branch 

 passes below and to the outside of the optic nerve, and divides into three 

 branches : an internal, to the internal rectus ; a middle, to the inferior rectus ; 

 and an external, to the inferior oblique. 



4. The Trochleator Patheticus. Fourth Pair. This is the smallest 

 nerve coming from the encephalon, not exceeding a sewing thread in thick- 

 ness. It arises by two roots from the upper anterior face of the valve of 

 the brain, just below the testes ; passing through the foramen lacerum 

 orbitale, it reaches the eye, and is distributed to the superior oblique 

 muscle. 



ICONOGRAPHIC ENCYCLOriEDIA. — VOL. II. 53 833 



