Sensori-motor disturbances resulting from gross lesions of the nervous system are, as a rule, easily demonstrated. Slight degrees of inco-ordination, however, associated with disturbances of consciousness and attention, are, by the ordinary clinical methods of examination, sometimes most difficult to discover. In psychic conditions, such as emotional and subnormal states, manic-depressive insanity and schizophrenia, sensori-motor disturbances may manifest themselves in the form of tremors, inhibitions, inco-ordination and accelerated or sluggish action.