The motor manifestation is the consequence of irritation at some point on a bulbo-spinal reflex arc; its abruptness and instantaneousness negative the possibility of recognising in it any sign of functional systematisation. It is not a co-ordinated act of a purposive nature, but a simple, unvarying, constant motor reaction to a particular stimulus. That its intensity should be in direct proportion to the intensity of the latter, changing from feeble contractions to a state of transient tetanus, is further proof of its spasmodic origin. When the excitation is at its maximum, there is sometimes involvement of the opposite side of the face, by virtue of the law of the generalisation of reflexes. It is true there is no association of pain with his attacks, as in so-called tic douloureux, but the spasm is heralded by a tingling sensation below and to the inner side of the outer corner of the eye. This sensation, "like an electric battery," persists during the spasm and disappears in the intervals. Its occurrence suggests that the ascending branch of the infraorbital nerve, springing from the trigeminal, is affected, and indeed pressure over its point of emergence evokes a certain amount of pain. Moreover, there is occasionally a flow of tears when the spasm is at its height. It may be difficult to decide whether this is the result of mechanical compression of the lachrymal gland or an exaggerated secretion of tears under the influence of stimulation of the lachrymo-palpebral twig of the orbital nerve. In any case the pathogeny of this facial spasm is entirely comparable to that of tic douloureux of the face, and it is quite within the bounds of possibility that a minute hæmorrhage--for the patient is of a very florid type--somewhere on the centrifugal path of the trigemino-facial reflex arc, may be giving rise to the phenomena. What we wish to insist on, however, is the dissimilarity between this facial spasm and tic. In the movements we have been describing we fail to distinguish any purposive element, any co-ordination for the fulfilment of a particular function: they are not imitative in character, nor do they express any sentiment; no impulse precedes their execution, no satisfaction follows. The patient's mental state presents no peculiarities, as far as we have been able to discover. There is no volitional debility or instability; if he cannot control the convulsions, it is to be remarked that he cannot control them even for a moment, whereas all sufferers from tic are capable of inhibiting it for a longer or shorter period by an effort of the will, by concentrating their attention on it.[169] The following remarks on this case are due to Professor Joffroy: