DISSECTION OF THE BRAIN. SI 
arises from the ventral surface of the medulla back of 
the pons. 
g, THE Factat or VII. cranial nerve arises from the 
outer side of the anterior border of the corpus trape- 
zoideum behind the origin of the trigeminal. 
h. Tue AupirTory or VIII. cranial nerve arises just 
outside of and behind the facial nerve. It is larger 
than the facial. 
i. THE GLOSSOPHARYNGEAL AND THE VacGus, the 
IX. and the X. cranial nerves, arise together by anum- 
ber of slender roots from the side of the medulla behind 
and to the outer side of the origin of the auditory nerve. 
j. THe Sprnat Accessory or XI. cranial nerve 
arises by a number of roots from the side of the cord 
and medulla, extending forward as far as the origin of 
the vagus nerve. | 
k. THe Hypoctossat or XII. cranial nerve arises 
from the ventral surface of the medulla close to the 
mid-line and just outside of the anterior pyramids, 
Ce tee INTERNAL STRUCRORL.OF THE BRAIN. 
1, The Cerebral Hemispheres (/ore-brain or pros- 
encephalon). 
With a razor kept wet with alcohol take off hort- 
zontal slices of the cerebral hemrspheres, cutting care- 
fully until the corpus callosum ts reached. 
a. Note the structure of the cerebral hemispheres: 
the outer cortzcal layer of gray matter folded into the 
interior at the sulci, and the inner or medullary por- 
tion of white matter—nerve-fibres. 
b. Notice the direction of the fibres of the corpus 
callosum, running transversely from one hemisphere 
to the other. 
