A last instance, published by Innfeld[137] as a case of "chronic progressive muscular spasm," is an unmistakable example of tic, in spite of the author's declaration that it does not correspond to any known morbid type and his attempt to liken it to chronic chorea. A boy of fifteen exhibited convulsive movements which had begun in the facial musculature and thence spread to the head, shoulders, and hands, and were accompanied with respiratory noises and involuntary exclamations. There was no alteration in sensation or in reflectivity, or in electrical excitability. Sleep banished while emotion aggravated the movements. VARIABLE CHOREA OF BRISSAUD If the disease of Gilles de la Tourette, by reason of the uniformity of its symptomatology and the regularity of its evolution, justifies its differentiation as a separate entity among the tics, a comparison of it with another type, of polymorphic manifestation, irregular evolution, and uncertain duration, may prove instructive. We refer to the affection described by Brissaud as variable chorea. The form of the motor reactions in this condition warrants the application to it of the term chorea, but the analogies the disease presents to tic are very close, nevertheless, and sometimes the two occur in the same individual. Patients suffering from variable chorea reveal the same mental abnormalities as are found among those who tic, while the troubles of motility are sometimes so similar to what we meet with in the latter that Gilles de la Tourette regarded the condition simply as one form of convulsive tic, the more so that it is occasionally accompanied by explosive utterance and even coprolalia. This view, however, is calculated to obliterate the distinctive characters of the two affections, and ought not to be entertained. We cannot do better than repeat Brissaud's original description: The use of the word chorea need occasion no ambiguity: the chorea consists in the appearance of meaningless and apparently idiopathic involuntary movements, whose repetition during rest and action alike is proof of their irrationality and incongruity; the duration of the symptoms may be limited as in chorea minor or Sydenham's chorea, or unlimited as in chorea major or Huntington's chorea. "Variable" is the epithet we apply to the chorea because of the lack of uniformity in its exteriorisation, the irregularity of its development, and the inconstancy of its duration. It comes and goes, waxes and wanes, vanishes abruptly to reappear unexpectedly; it is a neurosis without a characteristic march.