CoNTRARY to chronology, or the logic of first things first-but to nobody's surprisethe latest ideas about strokes are readily accessible, while much effort is needed to bridge the gap lying in the direction of their past.' Yet the essential observations go far back and are much hidden by contemporary, often ephemeral growth. We hardly get to see the wood for the leaves. Where are the stems that keep our knowledge green? 'Stroke' for us-unlike coup in French or Schlag in German-acquires its morbid meaning simply from the context. 'He had a stroke' needs no elaboration. Former ages, taking no semantic chances, would not let the word go unattended by a qualification such as 'paralytic' or 'apoplectic', used indiscriminately. In the Oxford English Dictionary the first synonym for the 'stroke of the palsy' is given as 'stroke of God's hands', 1599. Today, apoplexy sounds a little quaint. It is the classical striking off or down. The Latin equivalents morbus attonitus and sideratio-literally 'being thunderstruck'-suggest both a celestial force and an affliction of the mind.2 Embolism and thrombosis are usually traced, with good reason, to Virchow and the mid-nineteenth century. Thrombus, since antiquity, has been a coagulum, clot, or curd in blood and milk. In surgery it has done duty for the seal that is on a vessel punctured or severed. Embolus, long before Virchow, was in use for a variety of connotations different from his and ours. The odd, extra day that calendar-makers had to intercalate was an embolus. In surgeons' terminology it stood for throwing in of the humeral or femoral head to reduce a dislocation. In the seventeenth century the plunger of a syringe was an embole.' We do not say 'apoplegia' or 'paraplexy', although we might. In the Greek and English language, chance or euphony have fixed these near homonyms and synonyms to be the way they are. Paraplegia or paraplexia, for Aretaeus, was but a minor variant, a 'para' or 'near' apoplexy. It is the incomplete or circumscribed loss of function, the paresis 'of a part only', 'the letting go of touch and motion in either a hand or a leg'. Paralysis was the more technical term, for it was defined by Aretaeus as a pdresis-evidently the non-technical expression. Paralysis or paresis denotes the loss of function that affects motion-loss, he adds, of 'energeia': energy perhaps, but not quite; 'the thing inherent in work'.' All the terms: apoplexy, paraplegia, paresis, paralysis, here refer to the same sort of thing, or to degrees of it. 'Apoplexy is a paralysis', Aretaeus says, 'but a paralysis 1 Since this was written the student has been enabled to consult L. C. McHenry, Garrison's History of Neurology, Springfield, Ill., Thomas, 1969, pp. 370-87. 'E. Clarke, 'Apoplexy in the Hippocratic writings', Bull. Hist. Med., 1963, 37, 301-14. 8 References to old English usage from the Oxford English Dictionary. 'Aretaeus, the Cappadocean: The Extant Works, ed. and trans.