482 Drs. F. W. Mott and C. S. Sherrington. [Mar. 21, 



and knee. As the animal runs about it does not attempt to use the 

 leg ; the fore limb swings helplessly, with flexion at elbow and wrist 

 and adduction at shoulder, in much the same position as if carried 

 in a sling. The hind limb looks as if it were being held up so as to 

 be kept off the ground while the animal runs on three legs ; we are 

 inclined to think that this appearance is deceptive, and that the 

 position results from an equilibrium of the action of the muscles, in 

 which purposive action on the part of the animal does not play a 

 role. When the animal is allowed to climb a rope or the side of the 

 cage, the fore limb swings more or less helplessly, and is not used for 

 the climbing ; similarly, the hind limb is kept more or less flexed at 

 hip or knee, and is not used for the climbing. If the feeding-time be 

 deferred, and an animal, in which the apeesthete* limb is an arm, be 

 tested by offering it fruit after the sound arm has been secured 

 behind the back, there is no attempt to use the apsesthete limb for 

 reaching the food, but the neck is thrust forward in order for the 

 mouth to seize it. If the fruit be placed in the hand of the apaesthete 

 arm, the animal does not lift the hand, and appears quite unable to 

 do so, even though encouraged. If, however, the hands of a tame 

 normal monkey be secured behind its back, and, as it lies on the floor, 

 fruit be placed near it, the fruit is usually taken at once with the foot ; 

 but if the leg is apaasthete the fruit cannot be taken, although 

 in one monkey the attempt used to be made. The foot was rapidly 

 thrust toward the fruit by extension of hip and knee, but the foot 

 missed its object widely, i.e., by several inches, and the digits were 

 not moved, though the ankle appeared to be slightly plantar-flexed. 

 The impairment of motility in the limb ensues immediately upon 

 completion of the section ; that is to say, directly the effects of the 

 anaesthetic have passed off sufficiently to allow requisite examination 

 of the animal's ability to move its limbs, the above-described 

 inability is discoverable as fully developed as at any subsequent 

 period. We have kept the animals alive for various periods up to 

 and over three months, and there has been no obvious change in the 

 condition, either in the direction of improvement or the reverse. 

 In the case of the lower limb, after two or three months, the constant 

 position of flexion of hip and knee, on two occasions, gradually 

 induced a change in the muscles of the thigh, which prevented 

 hip and knee being properly extended, even by passive stretching. 



As to the nature of the disturbance of motility in the limbs, one 

 feature, namely, its peculiar topographical distribution, is salient 

 and constant. The defect in motility increases from the attached 

 base to the free apex of the limb ; so that, for instance, while com- 



* ATTO, aiffOavonai, " deprived of sensation," in distinction from ansesthete, 

 " devoid of sensation." We are indebted to Dr. Verrall, of Trinity College, Cam- 

 bridge, for the suggestion of this term. 



