O. exhibits a tic of the inferior maxilla. He protrudes and retracts his jaw alternately in his endeavour to elicit cracking noises from his temporo-maxillary articulations. At one time his hands used to join in the fray, the goal being to overcome the masseters and effect a sort of dislocation. A biting tic ensued. One day O. was alarmed to discover two dark patches on the internal aspect of the cheeks, but was reassured on learning from his sister--whose proclivities lay in a similar direction--that she had noticed the same in her own case, and that it was the result of constant nibbling at the buccal mucous membrane. Nor was this the solitary biting tic. Formerly a pencil or a pen-holder used to be unrecognisable at the end of twenty-four hours, and the handles of canes and umbrellas suffered as well. To obviate the nuisance he entertained the unfortunate idea of using metal pen-holders and carrying silver-mounted walking-sticks; but his teeth failed to make any impression on the objects, and began to break in consequence. The irritation produced by a small dental abscess proved an additional source of mischief, for he developed the habit of trying, with finger, cane, or pen-holder, to shake the teeth in their sockets, and was finally compelled to have the incisors, canines, and first molars drawn. Then he ordered a set of false teeth--a move that afforded a new excuse for a tic. Every moment the set was in imminent risk of being swallowed, so vigorously did his tongue and lips assail it. Fortunately such an accident has never occurred, although he has already broken several sets. Sometimes he would be seized with an insane impulse to take his teeth out, and would invent the flimsiest pretext for retiring; the set would then be extracted and immediately reinserted, to his complete satisfaction and peace of mind. An infinite variety of scratching tics must be added to the number. He has also a tic of phonation dating back to his fifteenth year. His custom was, when learning his lessons at school, to punctuate his recital of them with little soft expiratory noises that may still be distinguished to-day among a host of other tics. The following is his proffered explanation of the pathogeny of this "clucking" tic: