MOTOR CORTEX AXD INTERNAL CAPSULE IN AN ORANG OUTANG. 
155 
PtOLANDO. the posterior extremity of the superior frontal sulcus (superior prmcentral 
sulcus of Jensen), and consequently a small piece of the ascending parietal, and a 
considerable part of the ascending’ frontal convolution, with very small portions of the 
superior and middle frontal convolutions. All these were explored with the current 
mentioned above, but only the ascending frontal gave any residt. 
No final conclusions can be ascribed to this fact, owins: to reasons which have been 
already stated, although care was taken to irrigate with the mercurial lotion instead of 
carbolic. In the ascending frontal, the points indicated below by the numbers I, 
2, 3, 4, 5 from above downwards, were found to be excitable and produced movement 
as follows :—■ 
The movements were observed by Sir James Crichton Browne, Drs. Buxton, 
Walton, and Russell. 
Ascending Frontal Convolution. 
Number.* 
Charactei’ of movement. 
I 1 
i 
Shoulder abducted, whole upper limb extended with jnonatiun 
of wrist 
2 
Wrist, pronation; elbow movement (? character) 
3 
Fingers ail flexed. Wrist extended with (?) pronation 
4 
Index finger flexed 
5 
Tiiumb, slight abduction followed by flexion towai'ds palm 
We wish to point out that the order of representation in the above table is 
precisely the same as that observed in the Orang and also in the Bonnet Monkey. 
The movements were, for the most part, single, i.e., affecting only one segment of the 
limb, and were evidently primary in character (vide ‘ Phil. Trans.,’ 1887). It was, of 
com’se, impossible to investigate these points more minutely as the object of the 
exploration had been attained, but it seemed as if the portions of cortex intervening 
betw’een the aVjove foci were either altoo'ether inexcitable or much less excitable than 
the foci themselves. 
We think that it will be now admitted that we are in a position to assert that the 
character of the motor function of the cortex, whether topographical or physiological, 
is the same in the higher animals, proceeding from the lower Apes through the 
Anthropoids to Man. 
4. In complete accord with this we find that in the Orang no border centres of 
amalgamated function of contiguous areas of representation exist, such as, for instance, 
that in the Bonnet Monkey between the areas for t!ie limbs and face. 
5. We never observed epilepsy to follow excitacion of any part, although, as has 
been already described (p. 140) the electrodes were occasionally kept in contact 
* No. I was situated just below the level of the superior frontal sulcus, and No. 5 just above the 
middle of the genu, which was well marked, 
X 2 
