It is, indeed, this evolution of symptoms which is so characteristic of Gilles de la Tourette's disease. A careful scrutiny of recorded cases of tic, however, makes it abundantly clear that they do not all belong to the disease of convulsive tics; their localisation, form, and progress are so different that the effort to assimilate them to Tourette's disease would abolish the nosographical value of the latter. One patient may have an ocular tic all his life, and nothing else; the affection of another may be limited to a tic of the shoulder and arm; a third blinks and makes a facial grimace; a fourth is a coprolalic who has never suffered from tic. Are they all to be considered incomplete cases of the disease of convulsive tics? To answer in the affirmative is equivalent to a failure to appreciate the distinctive characters of a judiciously isolated syndrome, and a refusal to describe tics as they are met with in everyday life. One questions, in fact, whether some of the cases allotted to Tourette's disease really conform to it. Take an instance from Chabbert[133]: A woman, aged forty-two, had had an injury to the left side of her face at the age of nine, as a result of which appeared a convulsive facial tic, accompanied at times by hysterical attacks which continued for eight years. The tic itself, an abrupt contraction of the inferior portion of the left orbicularis palpebrarum, underwent no subsequent change, in degree or extent. At a later stage a fairly definite tendency to coprolalia became manifest. An unvarying post-traumatic palpebral tic in an hysterical subject cannot be said to constitute the syndrome of Gilles de la Tourette, in spite of the coprolalia. In another of his cases the diagnosis is no less open to doubt: The son of the previous patient was a youth of nineteen, with a bad heredity on the father's side. In boyhood he had been a somnambulist. Some months previously to his coming under observation he developed a convulsive tic limited to the frontalis. Stigmata of hysteria were present in dyschromatopsia, restriction of the visual fields, and left hemihyperæsthesia. A third case reported by the same author does probably belong to the disease of convulsive tics: A woman aged forty-four, of a strumous diathesis, exhibited tics of face and limbs, occurring in the form of attacks sufficiently violent to cause bruises, attacks which were invariably associated with coprolalia. In addition, she suffered from echolalia, echokinesis, and _folie du doute_.