Hysteria and neurasthenia are two diseases which we meet at every turn in our study; and if we remember that, according to Raymond, fibrillary chorea of Morvan, paramyoclonus multiplex of Friedreich, electric chorea of Hénoch-Bergeron, painless facial tic of Trousseau, and disease of Gilles de la Tourette-Charcot, are all mere varieties of myoclonus, which is itself a product of neurasthenia and hysteria, we are forced to admit that it is these conditions which dominate our conception of psycho-mental convulsive tic. Thus it comes to pass that tic is lost in a crowd of widely differing convulsive phenomena, and is threatened with the permanent loss of its distinctive characters, while hysteria itself is like to become a perfect Proteus once more. Neurasthenia too is again to sink to the level of a receptacle for all manner of ill differentiated conditions. We, on the contrary, feel it more than ever incumbent on us to resist the tendency to class in the same section facts which clinical observation distinguishes, otherwise hysteria and neurasthenia will soon signify nothing at all. If tic is to be considered one of the polymorphic manifestations of these diseases, we shall be transported back fifty years, to the time of the famous "chaos of neuroses," out of which, in some ways at least, Charcot finally produced order. TIC AND EPILEPSY The co-existence of epilepsy and tic has been noted sufficiently often to open the question of their possible relationship. Of course the mental state of epileptics is such as to favour the development of tics. Usually, however, the convulsive phenomena supposed to be of the nature of tic merit some other description. In the first place, they may be Jacksonian in type, and under these circumstances confusion is scarcely possible. It is not without interest to compare the gestures and stratagems of defence which sufferers from tic devise, with the procedures adopted by some Jacksonian patients, such as compression of the arm or wrist by the fingers, or by string or more elaborate apparatus. There might conceivably be some hesitation in making a diagnosis if it depended on these arrangements, but the mere observation of one actual attack will dispel all difficulties. We may mention the convulsive seizures of idiopathic epilepsy only to dismiss them. Loss of consciousness is an unfailing criterion. It is more especially the association of epilepsy with the ill-defined group of myoclonus that we propose to discuss. According to Maurice Dide,[160] myoclonus, which he calls motor petit mal, occurs in five per cent. of cases of epilepsy. Attention has also been directed to this question by Mannini[161]: