XI. THE MAMMALIAN BRAIN 
Material. —Each student should be provided with the head of 
a calf or sheep, obtained in as fresh a condition as possible from 
the abattoir. The head should be cut off well into the neck region, 
and the tongue left in place. The material is less expensive and 
more easily handled if the head is skinned, but at least one head 
should be sent with the skin on for the demonstration of external 
features and landmarks. The implements needed for the work 
are in addition to the usual dissecting instruments, a small saw, 
a % inch carpenter’s chisel, a wooden mallet, and bone forceps. 
Preparation of Material. —The specimen should be thoroughly 
washed under running cold water, and if it has been frozen it 
should be thawed before beginning the dissection. Make a rapid 
examination of the head externally, noting the relative position 
of various features, and identifying skeletal landmarks. Identify 
the structures shown in the cross section of the neck, and draw 
a diagram recording these. 
In case the specimen is not already skinned, remove the skin 
except around the mouth, the distal region of the nose, and the 
eyes, using for the purpose very sharp scalpels. The external 
ear may be removed with the skin. Note the adhesion of the 
skin to the frontal bone in the region medial to the superciliary 
arches where in the male the horns may be seen in various stages 
of growth. Remove the muscles from the lateral and posterior 
surfaces of the cranium, thereby exposing the temporal ridges and 
the occipital protuberance. Mark out with the scalpel lines 
along which to saw to remove the roof of the cranial cavity 
as follows: (i) an oblique line upon each side medial to and parallel 
with the superciliary arches, meeting each other in the midline 
anteriorly, and ending posteriorly just lateral to the temporal ridge; 
(2) an oblique line upon each side from the posterior end of the 
first line to the occipital foramen just medial to the occipital 
condyle. Use a small saw and take care to hold it at right angles 
73 
