There is no limitation of the movements to a special division of the body; on the contrary, they spread from one muscle to another, and from one segment to another, rapidly and arhythmically. The gait is by turns skipping, dancing, or stumbling, interrupted by falls or by abrupt jerks of the loins. Speech is uncertain or monotonous; writing is incorrect and badly formed, sometimes illegible. A fact of the utmost importance is that all these involuntary movements may be modified, abated, relieved, so to speak, by voluntary movements in an inverse direction. In some cases the power of willing is still sufficiently developed to permit of the patient's following his occupation. The steadily progressing increase in the seriousness of the motor trouble, paralleled by progressing mental deterioration, is one of the most significant factors in the differential diagnosis. It is precisely the variability of the symptoms that distinguishes variable chorea. C. Hysterical Chorea The conditions to which the name of hysterical chorea is applied may assume two forms, the commoner being known as rhythmical chorea, the other as arhythmical chorea. In the former case the convulsive movements are usually unilateral, being confined sometimes to a single limb, and reproducing, for instance, the actions of dancing (saltatory chorea), or of swimming (natatory chorea), or such professional movements as those of the blacksmith (_chorée malléatoire_). Occasionally there is a more or less faithful reproduction of deliberate and purposive acts in the form of attacks of varying duration, recurring, moreover--and this is their cardinal feature--at equal intervals. Under the title of disease of the tics two cases have been published by Nonne,[180] the first consisting of rhythmical twitches in a man of forty years, secondary to a head injury, the other presenting similar appearances, but concerning a young girl of eighteen years who had sustained a shock. In neither was there any sign of hysteria. The reporter animadverts on the designation "rhythmical chorea," and protests that the systematisation and co-ordination of the movements are very different from the clinical picture of Sydenham's chorea, while their rhythmical nature does not allow of their being classified as tic. Sometimes hysterical chorea is arhythmical--that is to say, the movements are irregular and contradictory, as in ordinary chorea. True chorea in cases of hysteria comes under this heading, as well as those cases where hysterical patients imitate the movements of chorea. The presence of the distinctive characters of hysteria makes a diagnosis of tic improbable.