1834.] Experimental Researches in Cerebral Physiology. 441 



This area is largely overlapped by the next one, III, III', excitation 

 within which is followed by movements of the hip, at some points the 

 flexors only, at others the extensors only, at others both sets of muscles 

 being called into contraction simultaneously. As will appear from 

 the overlapping of the areas in the figure, these movements of the hip 

 are apt to be associated with the rotatory aud bending movements of 

 the trunk above mentioned ; but in the anterior part of the area it is 

 generally the rotation of the trunk and pelvis which is first seen, and 

 this is followed by hip movements, whereas in the centre of the area 

 movements of the hip may be the first to appear, or with a very weak 

 excitation may be the only ones visible. 



The next area, IV, IV, is very extensive. It considerably overlaps the 

 areas II, II', and III, III', and extends to the posterior limit of the con- 

 volution. Its excitation calls up contractions of the thigh muscles, and 

 especially of the hamstrings, which in some parts are tbe only muscles 

 affected by weak stimulation — indeed, in some instances the contractions 

 of the individual hamstring muscles were perfectly localised. But in 

 most parts of the area, as the overlapping of the contours shows, 

 these movements are associated with those of other muscles, viz., 

 anteriorly with the trunk and hip muscles, and posteriorly with 

 muscles which move the ankle and toes. These associated move- 

 ments may be simultaneous, but are most commonly successive, as 

 when by stimulation of one point there was produced, first a contrac- 

 tion of one of the abdominal muscles, then of one of the thigh 

 muscles, and then of one of the muscles which move the ankle. 



In like manner tbe area marked V, V, may be looked upon as the 

 specialised part from which the movements of the ankle are con- 

 trolled, these being usually the first to appear on exciting the area, 

 although very generally associated with or followed by movements of 

 the hip and knee. And VI, VI', may for a similar reason be looked 

 upon as specially controlling certain movements of the toes, generally 

 associated, however, with other movements of the lower limb. As before, 

 mentioned with regard to the other areas, the particular movements 

 called forth differ according to the point in the area which is excited, 

 but our experiments do not as yet enable us to make sufficiently positive 

 assertions as to the localisation of these specialised points. 



In the two animals from which the excitable portion of the marginal 

 convolution has been removed, the resulting pareses of voluntary 

 movement, so far as these can be determined, are precisely such as 

 might be expected to occur from removal of those portions of the 

 cortex by which the voluntary movements of the muscles which are 

 called into action by stimulation of this convolution may be assumed 

 to be governed. Since, however, as Ferrier has shown, certain of the 

 muscles are also caused to contract by excitation of portions of the 

 external surface, the paralysis of these would not be so complete as of 



