Among the various noteworthy advances made by neurology since the beginning of this century none is more striking than that concerned with our knowledge of motor disease.
A single illustration will serve better than any long account to demonstrate this progress. In the third volume—devoted to diseases of the nervous system—of Sir William Allchin's "Manual of Medicine," published only twenty years ago and remarkably modern in its outlook, paralysis agitans finds a place under "Functional Diseases," between occupation neuroses and night terrors. Today, no student of the subject can pick up a neurologic journal, English or foreign, without a likely chance of finding therein contributions dealing with the phasic and static activities of the motor nervous system, with muscle tonus, extrapyramidal motor disease, postures, attitudes, and involuntary movements. Along with the advance of which these innumerable papers are the token, however, there has come increasing recognition of difficulties, or, rather
WILSON SAK. THE OLD MOTOR SYSTEM AND THE NEW. Arch NeurPsych. 1924;11(4):385-404. doi:10.1001/archneurpsyc.1924.02190340007002