I am conscious of very material gain. I do not tic so often or with such force. I know how to keep still. Above all, I have learned the secret of inhibition. Absurd gestures that I once thought irrepressible have succumbed to the power of application; I have dispensed with my para-tic cane; the callosities on my chin and nose have vanished; and I can walk without carrying my head in the air. This advance has not been made without a struggle, without moments of discouragement; but I have emerged victorious, strong in my knowledge of the resources of my will.... To tell the truth, at my age I can scarcely hope for an absolute cure. Were I only fifteen, such would be my ambition; but as I am, so shall I remain. I very much doubt whether I shall ever have the necessary perseverance to master all my tics, and I am too prone to imagine fresh ones; yet the thought no longer alarms me. Experience has shown the possibilities of control, and my tics have lost their terror. Thus have disappeared half my troubles. The same sagacity that O. displayed in analysis of his tics has enabled him to grasp the principles of their subjugation. Notwithstanding that his guarded prognosis is evidence for his appreciation of the hindrance his peculiar mental constitution is to a complete cure, he has impartially put on record his definite progress towards health of body and mind. * * * * * Such, then, is the faithfully reported story of our model, such are his confessions. During ten years' intercourse with sufferers from tic it has been our interest to analyse and reconstruct the pathogenic mechanism of their symptoms, and in the vast majority of cases it has been possible to determine the origin of the tics and to confirm the association with them of a peculiar mental state. We have thus been able to supplement earlier and weighty contributions to the subject by numerous suggestive instances, prominent among which is the case of O., whose spontaneous and impartial self-examination forms an invaluable clinical document. Its importance is enhanced by the fact that its observations are corroborated by a survey of other examples of the disease.