Victor Horsley

I. Note on some of the motor functions of certain cranial nerves (V, VII, IX, X, XI, XII), and of the three first cervical nerves, in the monkey (Macacus sinicus)

In the coarse of an investigation which we are making into the cortical representation of the muscles of the mouth and throat, we have experienced considerable difficulty in describing correctly the movements of these parts, especially when there was any question of bilateral action occurring. On referring to text-books we failed to find any solution of this difficulty, and we therefore determined to make a few observations of the movements evoked by stimulating the several cranial nerves supplying this region in the monkey so as to have a definite basis whereon to ground our observations of the movements obtained by stimulating the cortex.

A further minute analysis, by electric stimulation, of the so-called motor region of the cortex cerebri in the monkey (Macacus sinicus)

The present research, of which the following is a brief abstract, is in continuation of an investigation which we commenced two years ago, the first part of which is about to be published in the ‘Philosophical Transactions.’ In our former paper we described the results of a minute analysis, obtained by electrical excitation, of that part of the cortex in which Professor Ferrier had previously shown that the movements of the upper limb were chiefly represented.

VI. A record of the results obtained by electrical excitation of the so-called motor-cortex and internal capsule in an orang outang (Simia saturus)

Having been engaged for some time in investigating the representation of motor function in the cortex of the bonnet monkey, we thought it advisable to perform the same in an anthropoid as likely thereby to gain a closer insight into the modes of representation in man. We first describe the peculiarities noticeable in the configuration of the convolutions in the orang.

II. An experimental investigation into the arrangement of the excitable fibres of the internal capsule of the bonnet monkey (macacus sinicus)

After a historical introduction the authors proceed to describe the method of investigation, which was conducted as follows. The animal being narcotised with ether, the internal capsule was exposed by a horizontal section through the hemisphere. By means of compasses the outlines of the basal ganglia and capsule were accurately transferred to paper ruled with squares of 1 millimetre side, so that a projection of the capsule was thus obtained, divided into bundles of 1 millimetre square area. Each of these squares of fibres was then excited by a minimal stimulus, the same being an induced or secondary interrupted current. The movements were recorded and the capsule photographed.

II. A minute analysis (experimental) of the various movements produced by stimulating in the monkey different regions of the cortical centre for the upper limb, as defined by Professor Ferrier

The following investigation was undertaken as prefatory to a research into motor localisation of the spinal cord. Anatomy.—(1.) Attention is drawn to some minute details of the topographical anatomy of the upper limb centres as defined by Professor Ferrier. (2.) Outlines of the shape and arrangement of the fissure of Rolando, the precentral and intraparietal sulci.