72 
DR. C. E. BBEVOR AND MR. V. HORSLEY ON THE EXCITABLE 
bundle of fibres, excitation of which produced the movement. The third column 
gives the most posterior point or bundle of fibres at which the movement of a part 
could be elicited, so that the distance between the figures in these two columns gives 
the total or absolute extent of the fibres from which that movement of a part could 
be obtained. 
The intermediate or second column gives, in those cases where it was most marked, 
the point of maximal representation, i.e., of greatest intensity. 
Further, it is seen at once that the distribution of the fibres for any one part is not 
allocated to one small point in the capsule, but spread over it for a certain distance, 
so that the overlapping seen on the cortex occurs here, though to a larger extent. 
To further elucdiate the arrangement of the fibres and to facilitate future reference, 
we have constructed a series of diagrams (fig. 1, A-F.) on exactly the same scale 
as fig. 1 {i.e., twice the natural size), on which we have marked the extent of repre¬ 
sentation in the difterent groups of sections of each segment observed. In each figure 
the shaded part represents the fibres, excitation of wdiich produces movement of the 
given segment. The limits of these fil^i'es were obtained from the numbers of Table I. 
As we have already drawn attention in describing fig. 1, we would remark on the 
extraordinary diminution of the fibres before the successive appearance of the zones 
of the lenticular nucleus, and the equally striking increase of the fibres when these 
zones become visible, e.(j., Groups IV. and VII. 
Good examples of this are to be seen in the diagrams for the turning of the eyes, 
the small toes and hallux (fig. 1, B, Q, II). 
Physiological IIelations of the Basal Ganglia to the Internal Capsule. 
Although the ventricular surface of the caudate nucleus has been asserted to be 
excitable by Carville and Duret,'“ Ferrier,! and Minor,J we have fiiiled to obtain 
the slightest movement hj exciting the sectional surfaces of either of the basal 
ganglia. We do not advance these observations as of special value, considering that 
we removed the ventricular surface, but the contrast betAveen the absence of any 
result Avhen the ganglia Avere excited and the marked spasm Avhich immediately 
folloAved tlie application of the electrodes to the ca])side is in harmony Avith the 
observations of Franck and Pitres, § and Avith Avhose general deductions on this point 
Ave fully agree. 
To finally elucidate this important point, Ave have also excited the intra-ventricular 
surfaces of the basal ganglia, but Avithout any positive result. 
Consequently on revieAv of the expeilmental evidence, it seems to us most likely 
that the basal ganglia are really inexcitable. 
* Loc. cit. 
t Ferrier, loo. cit., p. 264. 
t ‘ Neurologisclies Centralblatt,’ Juue, 188o. 
§ hoc. cit. 
