404 APPENDIX. 
The brain falls out and rests with its dorsal surface on the cotton. 
Now remove the remainder of the dura mater, carefully cutting all 
adhesions to nerves. Remove also the pia mater, as far as that can be 
done without pulling off at the same time parts of the brain-sub- 
‘stance. Preserve the brain in the alcohol-formalin mixture. 
Study of the Brain.—In the study of the brain demonstration 
specimens are to be used as much as or more than your own specimen. 
See everything on a demonstration preparation before attempting to 
expose it in your own specimen. 
I. Examine the brain of a shark or of a frog. Cranial nerves may 
be neglected, but the divisions of the brain should be recognized in 
dorsal and ventral views and in longitudinal sections, and sketched. 
II. Read the general description of the cat’s brain (pp. 339-343), 
using your own specimen and a longitudinal section. Cut nothing 
on your own specimen except when especially directed to do so. 
Study the cavities on a preparation. Compare the diagrams (Figs. 
139 and 140) and the figures of the brain. 
III. Study the individual parts as follows. To avoid errors make 
constant reference to preparations and figures, 
1. The medulla (p. 344 and Figs. 138 and 141). Use your own 
specimen and a preparation and dissect out carefully the cranial 
nerves on your own specimen. 
2. ‘The cerebellum (p. 347). Study it entire, then to expose the 
fourth ventricle (p. 349) slice away with a very sharp scalpel one-half 
of the cerebellum by making a median longitudinal incision and then 
horizontal incisions. 
3. The pons (p. 347). 
4. The mesencephalon (p. 351, and Figs. 141 and 142). Study 
it first in a preparation. Then study the floor on your own speci- 
men; origin of third nerves. 
5. The diencephalon (Figs. 141 and 142). Study the roof and 
thalami and the pineal body on a preparation and on a longitudinal 
section; the floor on your specimen. 
6. The telencephalon (p. 357). (Note that only one side of this 
is to be dissected. ) 
a, Study it externally; sulci and gyri (Figs. 145 and 146). 
8, Examine a preparation showing the corpus callosum (Fig. 
147). Then slice away with a very sharp scalpel the top of one 
hemisphere nearly to the corpus callosum (see the preparation). 
Expose the corpus callosum on this side to its cranial and caudal 
borders, by searzng away the brain-substance at its side and above it. 
c. Raise the corpus callosum at the side and remove it, thus 
exposing the lateral ventricle in which note the septum pellucidum 
and fornix, the corpus striatum, and choroid plexus of the lateral 
ventricle (Fig. 148). (These are to be exposed on one side only, 
the other being left intact.) 
d, Expose the anterior and inferior horns of the ventricle and 
find the hippocampus, the fimbria, caudal part of the fornix, the 
ra 
