38 
BULLETIN OF THE LABORATORIKS 
furnished the sections most frequently described and figured beyond. 
Ether was employed as an anesthetic, and the skin was parted down 
the median line of the head and the skull removed over the anterior 
and middle parts of the left hemisphere. The current used was from 
one Grove cell and was just enough to operate the induction-coil, pro- 
ducing an irritation easily endured by the tongue When the elec- 
trodes were introduced at a. Fig. 4, Plate V, (at about the anterior 
one-third, near the median line and corresponding approximately to 
Munk’s region C of the dog) a forward and outward motion of the 
right fore leg was produced. A stronger current produced an electro- 
tonic contraction of the muscles of the whole right side. At the point 
about 5 mm. behind and a little outward from the above (corres- 
ponding to about the posterior margin of Munk’s region D), the stim- 
ulus produced a straightening of the right hind leg. At the point c, 
about 8 mm. behind and near the median fissure (corresponding to 
about Munk’s region F, near the median line), the stimulation resulted 
in a sharp contraction of the orbicularis palpebrarum and orbicularis 
oris of the right side and some feeble contraction of the facial muscles 
of the left side, probably due to superficial irradiation. 
At the point about 8 mm. behind c, and farther from the me- 
dian fissure, (corresponding to the anterior margin of Munk’s region 
A,) the insertion of the electrodes produces no motor disturbances nor 
did any point back of d. By a series of trials it was found that the 
electrodes produced some motor disturbance of the fore leg at all 
points within the area marked A, but not beyond it. 
The area B likewise marks about the limits of the hind leg region. 
An area of about 5 sq. mm. was then removed from the cortex of the left 
side in the fore leg region at about a. The wound was then dressed and 
the animal allowed to recover. The power of abduction of the right fore 
leg was lost. After some time another portion of the cortex was re- 
moved, a little back of on the left side. After recovery it was found 
that the animal was blind in the right eye. These experiments serve 
to locate some of the motor and sensory regions of the cerebral cortex 
for the subsequent histological works. 
It may be of interest to note also one of the series of experiments 
of electrical stimulation upon the Raccoon, Procyon lotor, which has 
been employed for comparative study. The animal was a male about 
three-fourths grown. Just enough current was used to drive the coil. 
Ether and chloroform mixed were the anesthetics employed. 
