About the age of seven or eight a little boy or girl--for the sexes are affected equally--commonly with a wretched family history, begins to exhibit a series of tics. The attention of the parents is soon drawn to the fact, but they seldom give much heed at first, since the twitches are limited preferably to the facial musculature. At this stage, too, expiratory laryngeal noises are occasionally superadded. The movements may be confined for a long time to the face, but under the influence of causes very difficult to determine they gradually invade the shoulders and the arms. First one shoulder is shrugged and then the other, then the trunk is inclined _en masse_ to right or left; then the patient waves his hands or his arms, or bends backwards and forwards, or jumps up and down, flexing the knees alternately and tapping with his feet. The muscles of the larynx sometimes participate in the abnormal functioning, whence it is that many sufferers from tic give vent to quick expiratory "hems" and "ahs," which coincide often with the twitches of trunk and limbs. The disease may be limited to this stage, but it is not uncommon to find, a few months or years after the beginning of the facial movements, that the inarticulate laryngeal sound becomes organised and develops in a particular direction, thus, in a sense, showing a pathognomonic value. Under the influence of causes whose action we are, in the majority of cases, powerless to appreciate, the patient gives vent one day to a word or short phrase of a quite special character, inasmuch as its meaning is always obscene. These words and phrases are exclaimed in a loud voice, without any attempt at restraint. There must be a complete absence of the moral sense where there is coprolalia such as this; at the moment of the ejaculation some irresistible psychical impulse must drive the patient to utter filthy words unreservedly and with no consideration for other people. Another psychical stigma--echolalia--is occasionally, though less frequently, observed in these cases. Such, then, is Gilles de la Tourette's disease, a clinical type of which many examples have been recorded. We do not think, however, that all tics can be brought under the same category; we lose sight of its distinguishing features if we make the attempt. Of course _fruste_ and atypical cases are encountered, but even in them it is rare not to find a certain degree of mental instability in dependence on which echolalia and coprolalia rest, so completing the morbid syndrome, and it is important to recognise the successive development of these various constituents.