Page:Proceedings of the Royal Society of London Vol 60.djvu/445

Rh applied to a toe evokes always, so far as I liave seen, flexion of ankle and k n e e ; usually of hip also. This movem ent is “ deliberately ” executed, and always institutes a m aintained posture.

If finger (or toe) of both rig h t and left limb be placed together in the hot water, there results sym m etrical reflex movement of both the rig h t and the left fore limbs (or hind limbs), leading to assum ption of a fairly symmetrical posture by the rig h t and left limbs respectively, 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 consideration.

Not the least interesting p art 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 rig h t 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 w hen the rig h t 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 th e 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 rig h t foot breaks down the posture assumed by the right arm, and conversely, and even moi’e easily, stimulation of the rig h t 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 right arm or by the right leg. If the right pinna is pinched when both arms are in this cataleptoid posture, complete inhibition can be readily exerted on the right arm, but usually only partial relinquishm ent 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 stim ulation 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