In a case recorded by Chipault and A. Chipault,[42] and characterised by brief epileptiform attacks involving the left side of the face, cerebral exploration proved ineffectual, but at the post-mortem a subcortical glioma of the size of a cherry was discovered underneath the posterior end of the second frontal convolution. Is a case of cerebral tumour to be labelled _tic_? It is quite exceptional, in fact, for lesions of the cortical facial centres to give rise to muscular movements suggesting facial tic. Take another instance: An interesting case (says Brissaud), and one that is everywhere quoted, is reported by Schultz, in which an aneurism of the vertebral artery, at the point where the basilar arises, compressed the trunk of the left facial nerve, and occasioned a "tic" of ten years' duration. As a matter of fact, one could not have a better example of _spasm_ pure and simple. Féré[43] cites the following incident in support of the contention that encephalic trauma may engender a tic: A man in falling on his head sustained an injury to the cranial vault over the posterior section of the left parietal bone, at a spot exactly corresponding to the posterior part of the angular gyrus, and immediately became afflicted with a convulsive tic of the zygomatics and orbicularis palpebrarum on the right. Conformably to Ferrier's experimental localisation of the motor centre for the eye muscles and lids in the angular gyrus, irritation of this centre by the cranial injury was the diagnosis made. The proffered interpretation of the motor phenomena by cortical excitation is entirely justifiable, but no convulsion consecutive to traumatism can ever pass muster as a tic. A no less frequently quoted experiment of Gilbert, Cadiot, and Roger,[44] supposed to confirm certain results obtained by Nothnagel, is now a standard case in the history of tic hypotheses. The animal in question was a dog affected with spasmodic twitches of the ear, which the successive removal of cortical facial centre, internal capsule, corpora striata, and cerebellum, signally failed to alleviate, and which disappeared only with the destruction of the corresponding nucleus in the pons. Their inability to find any anatomical change determined the experimenters in favour of the view that the trouble was functional, and they described it as a tic. It would be foolhardy to deny the existence of a lesion on the ground that it was not discovered. Negative findings of this sort are valueless. The sole conclusion to draw from the incident is the all-important rôle played by the bulbar centres in the production of convulsive movements, which are in such circumstances, of course, nought else than spasms.