We should like, however, to allude to a matter of clinical observation that we frequently have had occasion to remark. What simulates muscular enfeeblement in the subject of tic is often nothing else than a want of accuracy and _adresse_ in the performance of a given movement. For instance: S. enjoys robust health; his only trouble is a lack of accurate control over his limbs. His execution of the most elementary movements is incorrect. There is no tremor, no jerkiness, simply a loss of the sense of position. He never knows whether he is holding himself straight, whether his arms are exactly horizontal or his shoulders symmetrical. Often he confuses right and left, and when requested to perform some act on one side, he declares he is tempted to perform it simultaneously on both. The order to fold his arms and rotate the upper part of his body to the right evokes an inconceivable display of contortions. In the attempt to bend his head and body backward, fear of losing his balance causes him to twist and turn about most strangely, and the remark that all this he might avoid by merely putting one foot further back seems to cause him infinite surprise. Or again: The absence of precision in Mademoiselle R.'s movements, her habit of arresting the action before attaining the desired end, are not to be ascribed to any feeling of discomfort, but to her ignorance of the amplitude of her efforts, and of the position of her limbs. Her acts are always feeble, hesitating, and curtailed, a curious mixture of muscular languor and vigilance, "as if she were afraid of breaking herself." She appears to be constantly seeking some new position for herself, and to be as constantly oblivious of her actual attitude. With eyes closed, however, she indicates the relation of her limbs exactly. Another example is furnished by the case of L., to which reference is made on p. 135. There is no call to multiply instances. Enough has been said to demonstrate the frequent occurrence, if not of motor inco-ordination, at least of faulty orientation in space and of defective estimation in regard to the range and intensity of voluntary movements, among the subjects of tic. The topic is a very interesting and fruitful one, on which considerable light may be thrown by the application to it of the results of Pierre Bonnier's[54] remarkable studies on the sense of attitudes, a subject that we intend to develop on another occasion. FREQUENCY AND RHYTHM--RHYTHMIC TIC