ENCEPHALIC NERVE 447 



the superior laryngeal nerves, the finer are to the thick only as 2 to 1. 

 On the other hand, in the inferior laryngeal nerves and the pharyn- 

 geal branches, the thick fibres are to the fine as 6, or even 10, to 1. 

 All these fine fibres are not, however, derived from the great sym- 

 pathetic; but mostly from the ganglion-cells on the original roots of 

 this nerve. (Koltiker.) The eleventh pair (accessory of Willis) is 

 perhaps also in part sensitive; but has no cells, and, so far as is 

 known, presents nothing peculiar. 



The motor encephalic nerves are the third pair (oculo-motores); 

 fourth pair (patheticus) ; sixth pair (motor externus) ; seventh pair 

 (facial), and twelfth pair (hypoglossal). All these present the same 

 conditions as the anterior roots of the spinal nerves, except that all 

 of them anastomose with sensitive nerves, and thus carry sensitive 

 as well as motor fibres to the muscles. A ganglion is also found 

 in the facial nerve (intumescentia ganglioformis) ; and also on the 

 third pair in the ox, according to Eosenthal and Purkinje. This 

 occurrence of new cells in motor nerves is not yet explained. 



Terminal loops within the trunks of the encephalic nerves had 

 been noticed by Grerber, and since by Valentin. Their significa- 



Fig. 290. 



Outer wall of the nasal fossa with the three spongy bones and meatus ; the nerves being shown as 

 they would appear through the membrane if it were transparent, a Olfactory process, b. Olfac- 

 tory bulb (represented rather too short), resting on the cribriform plate. Below is seen the plexi- 

 form arrangement of the olfactory filaments on the upper and middle spongy bones, c. Fifth nerve 

 within the cranium with its Gasserian ganglion, d. Its superior maxillary division, sending 

 branches to Meckel's ganglion, and through that to the three spongy bones, where they anastomose 

 with the olfactory filaments, and with (s) branches of the nasal division of the ophthalmic nerve. 

 o. Posterior palatine twigs from Meckel's ganglion supplying the soft and hard palate, t. Orifice 

 of the Eustachian tube. From Simmering ; two-thirds diameter. 



