88 



THE NERVOUS SYSTEM 



to a very limited degree separated from the rest and are combined with 

 it to form the unity of the organism. We describe them separately, 

 but in life these three sets of nerves act invariably more or less together. 



These same considerations are 

 separate only anatomically. 



true also of the ''separate' 5 nerves 



FIG. 44 



I. olf. 



II. opt. 

 III. ocm. 



IV. troch. 

 V. trg. 



VI. abd. 



VII. fac. 



VIII. acust. 



IX. glossph. 



X. vag. 



XI. access. 

 XII. 



en 



The base of the brain, showing especially the apparent origins of the cranial nerves: I-XII, 

 the respective cranial nerves; JR, island of Reil; h, hypophysis cerebri; th, optic thalamus; cc, 

 corpora albicantia; gm, mesial geniculate body; gl, lateral geniculate body; py, pyramid; ov, 

 olivary body; CV1, first spinal nerve (cervical). (Schwalbe.) 



The Cranial Nerves. These are twelve in number in each side of the 

 body. They are known by their respective names, but often, especially 

 in the newer books, also by numerals, according to this list: 



Olfactory, or first. 

 Optic, or second. 

 Motor oculi, or third. 

 Pathetic, or fourth. 

 Trigeminal, or fifth. 

 Abducens, or sixth. 



Facial, or seventh. 

 Auditory, or eighth. 

 Glosso-pharyngeal, or ninth. 

 Vagus (pneumogastric), or tenth 

 Spinal accessory, or eleventh. 

 Hypoglossal, or twelfth. 



