Cataleptoid Reflexes in the Monkey. 413 



applied to a toe evokes always, so far as I have seen, flexion of ankle 

 and knee ; usually of hip also. This movement is " deliberately " 

 executed, and always institutes a maintained posture. 



If finger (or toe) of both right and left limb be placed together in 

 the hot water, there results symmetrical reflex movement of both the 

 right and the left fore limbs (or hind limbs), leading to assumption 

 of a fairly symmetrical posture by the right and left limbs respec- 

 tively, the posture being similar to but duplicate of that evoked in 

 the one limb only on excitation of that limb. This may appear a 

 self-evident sequel to the observation given earlier, but is not so 

 when an observation immediately to be mentioned is taken into con- 

 sideration. 



Not the least interesting part of the reflexes under consideration 

 is a remarkable glimpse which they allow into the scope of reflex 

 inhibition as regards the co-ordinate of movements of the limbs. 

 Although the posture taken up by the right fore limb consequent 

 upon excitation of a finger is symmetrically duplicated by the left 

 limb when both hands are simultaneously stimulated, the effect of 

 excitation of the two hands does not lead to symmetrical posture if 

 the excitation be not synchronous but successive. If when the right 

 arm has already assumed its posture in response to an excitation of 

 the right hand, the left hand be stimulated, there results, while the 

 left arm in obedience to the excitation is lifted and placed in the 

 flexed posture, an immediate and, if the stimulus be at all more than 

 slight, complete relaxation of the right arm. The right arm drops 

 flaccid while the left is raised and maintained in the raised attitude. 

 Similarly, excitation of the right foot breaks down the posture 

 assumed by the right arm, and conversely, and even more easily, 

 stimulation of the right hand breaks down a posture assumed by the 

 right leg. Again, a nip of the right pinna causes relinquishment of 

 a posture assumed by the righb arm or by the right leg. If the right 

 pinna is pinched when both arms are in this cataleptoid posture, com- 

 plete inhibition can be readily exerted on the right arm, but usually 

 only partial relinquishment can be induced in the left arm. To exert 

 complete inhibition upon the posture of the left arm, the pinna 

 pinched must be that of the left side. Similarly the posture reflexly 

 evoked by appropriate stimulation of either hind limb can be 

 inhibited by excitation of either pinna or of either fore limb, but 

 predominantly by pinna and fore limb of the same side as the limb 

 to be inhibited. The inhibition of the hind limb is much more easily 

 elicited from the opposite hind limb than from the opposite fore limb 

 or opposite ear. I have never yet seen it obtained diagonally upon the 

 fore limb from the opposite hind limb. 



The movements obtained in the limbs by exciting the limbs them- 

 selves are only cited above as examples to illustrate the general 



