Among the various functions which physiologists have attributed to the cerebellum, one only has been generally admitted in latter times; that is the co-ordination of movement The repeated experiments of Flourens, confirmed by those of MM. Bouillaud and Longet, seem to prove that the injury or absence of the cerebellum causes a confusion in the movements similar to that induced by intoxication, and that this organ is, in fact, the regulator of motion. Still pathological anatomy does not agree in this respect with the experiments made upon animals. Perfect integrity of function, and especially of locomotion, has been observed in congenital absence of the cerebellum. A great number of observations made by M. Andral prove that the cerebellum may be diseased while movements do not cease to be coordinated. The recent investigations of M. Duchenne, of Boulogne, also contradict the theory of Flourens, and it is now perfectly well known that the greatest disorder may exist in the movements without the slightest indication of lesion in the cerebellum.