In Ehret's view the fact of loss of volitional control argues the psychical nature of the affection, and a similar opinion is held by Thiem, Jacoby, and Wolff, who attribute the analogous cases they report to a sort of traumatic neurosis in which the psychical element is preponderant. Needless to remark, the patients in question were not suffering from hysteria. In this connection ought to be recalled the cases described by Raymond and Janet[104] under the title of "tics of the foot." The first was a woman thirty-seven years old, who as she walked used slightly to invert her left foot, forcibly dorsiflex the great toe, and separate the remaining toes widely one from the other. Notwithstanding its painful nature, the condition had persisted for seven years, and had originated in a very interesting way. She happened to be undergoing a course of mercurial inunction at the same time as she was troubled with a corn. The idea struck her that perhaps the application of the ointment to the corn might prove efficacious, but while trimming the latter some days later, she had the misfortune to cut herself. Dread of the possible evil effects of the injury was followed on the morrow by an accession of cramps in the foot, the continuance of which led to the deformity that ever since had made walking a misery. The other patient was a young man twenty years of age, whose gait used to be arrested, after a walk of ten minutes, by sudden and vigorous plantar flexion of his right toes. Momentary repose sufficed to make the spasm disappear, but it constantly recurred. Re-education and psychotherapy effected a cure in each instance, so that their psychical nature cannot be called in question, nevertheless the painful character of the affections must not be forgotten, and since the occasions of their manifestation were confined to the act of walking, they correspond rather to "functional" or "professional cramps." In any case, they cannot be confounded with the painful cramps of the calf muscles that characterise certain toxæmias and infections (alcoholism, cholera, etc.). On the other hand, there can be no doubt of the existence of definite tics of walking--widely varying functional derangements of tonic or clonic type, distinguished by the unexpected interruption of ambulatory rhythm. We have met with a patient (says Guinon) who would abruptly halt and bend his knees at though he had just received a violent blow on the hock for which he was unprepared. To see him, one would have thought he was about to sink to the ground. Such tics of genuflexion are not particularly uncommon. Oddo[105] has recently recorded a very instructive example, whose pathogeny he has been at pains to elucidate.