As far as we are concerned, the outcome of the whole matter is simply this: if tic is doomed to be used indifferently for convulsion, its retention in scientific terminology is unjustifiable. Rather, then, than widen its application, we prefer to restrict it; we shall employ the term convulsion in its most general sense of "any anomaly due to excess of muscular contraction," of whatever variety or origin; and we shall limit the use of the word spasm to phenomena the result of irritation at any point on afferent or efferent reflex paths, or in reflex bulbo-spinal centres. In thus indicating our position, we find ourselves once more in accord with generally received opinion since the days of Charcot. These views have been excellently expressed by Guinon: Convulsive movements differ widely in kind. Some consist of localised spasms in the domain of a motor or mixed nerve, most frequently one of the cranial series--in especial the seventh--consecutive to some anatomical lesion, central or peripheral. The great majority of observers, French and foreign alike, are in the habit of designating such movements "tics." ... But they are only partial convulsions limited to the area of some one nerve, not true convulsive tics, differing alike in essential features and concomitant symptoms. From the anatomo-pathological standpoint, moreover, lesions are as constantly present in the one as absent in the other. The opinion of Brissaud on the subject coincides with our own. * * * * * If we suppose now that the cortex ceases to act as a surface of peripheral excitation, and becomes itself a reflex centre, we note at once a complete change. The modification effected by the cortex on afferent impressions is obvious in altered motor reactions, which appear with the stamp of cortical intervention, herein differing from bulbo-spinal phenomena. To this category belong the tics; we shall soon see why and how. Conformably, then, to convention sanctioned by usage, and especially by the teaching of Charcot and Brissaud, we have given a precise definition to the word spasm, and we can only solicit its general adoption. To resume briefly the argument we have advanced in the foregoing paragraphs, we maintain: If in a given motor phenomenon there is no evidence of actual or previous cortical intervention, it is not a tic. If the motor reaction is consecutive to pathological irritation at any point on a bulbo-spinal reflex arc, it is a spasm. If the cortex is or has been involved in its production, it is not a spasm. Should it present, in addition to the fact of cortical participation, certain distinctive pathological features, it is a tic. It is precisely these distinguishing characteristics that we shall now proceed to examine, preluding our study of them with one or two physiological considerations.