Sign of Diffuse and Focal Brain Damage *-I

Dr. William Croone, who at his death in 1684 left plans for the lectureship he had designed to found, was interested in the nature of, and the laws governing, muscular motion, and it is upon one aspect of this subject that I should like to speak today-namely, the particular disturbance of psychomotility that is known as perseveration. The phenomenon is not to be confused with persistence or perseverance, which is tested by setting a task, without a time limit, and observing how long the subject sticks to it (Woodworth and Marquis, 1949). Perseverance is voluntary, perseveration involuntary; and this is the principal difference between the meanings of the two like-sounding terms (Yates, 1960), although the point is not made in standard dictionaries of medical terms (Meyers, 1932 ; MacNalty, 1961; Dorland, 1965).