It may sometimes happen that the manifestations of stereotyped acts consist in the assumption of attitudes, but in spite of their affinity to the tics we deem it preferable to reserve the term "stereotyped attitude" or "akinetic stereotyped act" for cases where the motor reaction is clothed in the form of a normal movement. As it is inaccurate to describe as a tic a repeated gesture whose execution is normal in degree and in rapidity, so the mere immobility of a limb, or the prolonged contraction of a muscle, ought not to be called an attitude tic if the muscular effort does not differ from that which a healthy person would make to preserve the same position. In such circumstances we say that it is a stereotyped gesture or attitude. For the diagnosis of tic it is insufficient to establish the existence of a transient or permanent muscular contraction, and to note the inopportuneness of the movement; the contraction must be abnormal in itself, its abruptness unwonted and its intensity excessive--in short, it must be a convulsion; and finally, its repetition must be continued and exaggerated. We have felt that some such explanation as the foregoing is required to justify our use of the term tonic or attitude tic, to whose close intimacy and association with the better-known type pathogeny and clinical observation alike bear witness. In any case such terms as myotonus or myoclonus are too comprehensive, in view of our present-day knowledge, to specify the particular motor affection with which we are concerned. * * * * * As a general rule it is only one part or segment of the body that is immobilised by a tonic tic, but in regard to the possibility of a general involvement, the following instance[50] may be cited, although we do not think it can be considered decisive: A man thirty-two years old, who had recovered from a first attack of mental torticollis, underwent a relapse in quite a different form. If when walking with his head perfectly straight he were asked to go round to the right, he instantly appeared to become rooted to the spot and could not turn even his head in the required direction; at the same time he felt a compression of his throat as if he were being strangled, and for a few seconds he experienced acute anguish. A moment later he was all right again, and his action unimpeded. Without going so far as to classify this incident as a tic, and without venturing to assert the existence of a _tic of immobility_, one cannot but be struck with its analogy to the attitude tics of which we have been speaking, and to catatonic conditions met with in the insane, of which too the pathogeny presents more than one point of similarity with that of this species of tic.