When L. was eight years old choreiform movements of the right arm began to appear, and soon rendered writing an impossibility. The disease continued for so long a time that one might not unreasonably expect to find considerable actual impairment of her caligraphy. As a matter of fact, it is scarcely affected: the patient can make her letters correctly, but after each letter she lifts her pen to allow her fingers to perform an abrupt movement, then she proceeds. It cannot therefore be considered a true writers' cramp, but when she had learnt to write with the other hand it was not long ere that became the seat of a genuine cramp. The moment she attempted to make the pen move over the paper her grasp of it tightened and her fingers stiffened; her wrist would no longer answer her. To obviate the trouble she used a pencil, at first with complete success; but the cramp occurred afresh, and she gave up writing altogether. Prolonged holidaying, however, and respite from the exercise, had a salutary effect, and to-day there is no trace of former mischief. CHAPTER XVII PROGNOSIS The prognosis in a case of tic depends solely on the mental state of the patient. After what has been said of the rôle played by psychical disorders in the genesis of tic, we can readily comprehend the reason for this. The intensity and tenacity of any tic are determined by the degree of volitional imperfection to which its subject has sunk. He who can will can effect a cure; be it a simple tic, or be it a case of Gilles de la Tourette's disease, if he can struggle long and energetically, the tic's doom is sealed. Permanent cures have undoubtedly been obtained, but they are the exception. Left to himself, the victim to tic can seldom escape from it. As far as life is concerned, tics are harmless, yet, according to Gilles de la Tourette, the prognosis is by no means always unchanging. The establishment of a tic is never followed by its ultimate disappearance; it may be modified in all sorts of ways, yet the expert observer will not fail to mark its presence. A complete cure is not to be expected, for however much paroxysms may be alleviated and their frequency reduced, the morbid condition has become a sort of function, a product of the patient's mental constitution.