Localisation of Function in the Lemur’s Brain. 137 
Stimulation Experiments. 
These were five in number. In all cases the anesthetic employed was 
ether, and anesthesia was maintained until the animal was killed at the 
conclusion of the experiment by an overdose of chloroform. 
‘The brain was exposed in the usual way, care, of course, being exercised 
not to injure its surface, nor to wound any large vessels. Its surface was 
explored by the usual two-point platinum electrodes connected to the 
secondary coil of a du Bois Reymond’s inductorium. The primary circuit was 
arranged for faradisation and included one cell. The approximation of the 
secondary to the primary coil was such that the current as tested by the 
tongue of the operator could be felt as a little more than a faint tickling. In 
some experiments Sherrington’s unipolar method* was used. Professor 
Sherrington was good enough to furnish us with one of his own electrodes 
for the purpose. The results obtained by this method were identical with 
those obtained by the two-point electrodes. It did not appear to us so easy 
to evoke movements by the single electrode, probably because the number of 
cortical cells excited is smaller than when two are used. The double-point 
electrodes, moreover, possess the advantage of being so readily tested in 
relation to strength of current by application to the operator’s tongue. 
Short protocols of the five experiments performed are as follows :— 
Lemur 1. Lemur catta.—Right hemisphere exposed in frontal and central regions, 
and explored with single-point and double-point electrodes, Resulting movements 
noted. 
Lemur 2. Lemur catta.—Experiment on Lemur 1 repeated, and some details of map 
made at the first experiment filled in and corrected. At the conclusion of this, 
the posterior part of the hemisphere was exposed, and its posterior pole excited ; no 
definite eye or other movements were thereby elicited. 
Lemur 3. Lemur macaco._,The same experiment repeated ; in this case the excitable 
area did not extend quite so far posteriorly as in previous experiments. 
Lemur 5. Lemur catta.—Stimulation of the occipital region, even with stronger 
currents than those usually employed, produced no effects, although stimulation of the 
anterior eye centres produced eye and head movements as in previous experiments. The 
occipital region on both sides was investigated. 
Lemur 6. Lemur catta.—Confirmatory experiment, the special object of which was 
to determine the posterior limit of the excitable area. No movements were evoked by 
stimulation of occipital regions, although these were better exposed than in previous 
experiments and explored on all surfaces. 
General fesults of Stimulation EHuperiments. 
The convolutional pattern of the brain, as will be seen by looking at the 
accompanying figure (Plate 2, fig. 1), is a simple one. , 
* As described in a paper by Fréhlich and Sherrington, ‘Journ. of Physiol.,’ vol. 28, 
p. 14, 1902. 
