Galen, or CLAUDIUS GALENUS, a celebrated Greek physician, was born at Pergamus, in Mysia, 131 A.D. In his nineteenth year he began the study of medicine, first at Pergamus, afterwards at Smyrna, Corinth, and Alexandria. On his return to his native city in 158 he was at once appointed physician to the school of gladiators. But six years later he went to Rome, where he stayed for about four years, and gained such a reputation that he was offered, though he declined, the post of physician to the emperor. Scarcely, however, had he returned to his native city when he received a summons from the Emperors M. Aurelius and L. Verus to attend them in the Venetian territory, and shortly afterwards he accompanied or followed them to Rome (170). There he remained several years, though how long is not known precisely: at all events he attended M. Aurelius and his two sons, Commodus and Sextus, and about the end of the 2d century was employed by the Emperor Severus. If the statements of one of his Arabic biographers, Abu-'l Faraj, be correct, he must have died in Sicily about the year 201, though the exact place and date of his death are not known with certainty.
Galen was a voluminous writer not only on medical, but also on philosophical subjects, such as logic, ethics, and grammar. The works that are still extant under his name consist of 83 treatises that are acknowledged to be genuine; 19 whose genuineness has been questioned; 45 undoubtedly spurious; 19 fragments; and 15 commentaries on different works of Hippocrates. His most important anatomical and physiological works are De Anatomicis Administrationibus, and De Usu Partium Corporis Humani. As an anatomist, he combined with patient skill and sober observation as a practical dissector—of lower animals, not of the human body—accuracy of description and clearness of exposition as a writer. He gathered up all the medical knowledge of his time and fixed it on such a firm foundation of truth that it continued to be, as he left it, the authoritative account of the science for centuries. His physiology does not, according to modern ideas, attain to the same level of scientific excellence as his anatomy. He is still dominated by theoretical notions, especially by the Hippocratic four elements (hot, cold, wet, and dry) and the Hippocratic humours. His therapeutics are also influenced by the same notions, drugs having the same four elemental qualities as the human body; and he was a believer in the principle of curing diseases traceable, according to him, to the maladmixture of the elements, by the use of drugs possessing the oppo- site elementary qualities. His pathology also was very speculative and imperfect. In his diagnosis and prognosis he laid great stress on the pulse, on which subject he may be considered as the first and greatest authority, for all subsequent writers adopted his system without alteration. He likewise placed great confidence in the doctrine of critical days, which he believed to be influenced by the moon. In materia medica his authority was not so high as that of Dioscorides. Numerous ingredients, many of which were probably inert, enter into most of his prescriptions. He seems to place a more implicit faith in amulets than in medicine, and he is supposed by Cullen to be the originator of the anodyne necklace which was so long famous in England. The subsequent Greek and Roman medical writers were mere compilers from his writings; and as soon as his works were translated (in the 9th century) into Arabic they were at once adopted throughout the East to the exclusion of all others.
GALENICAL, GALENIST, are words having reference to the controversies of the period of the revival of letters, when the authority of Galen was strongly asserted against all innovations, and particularly against the introduction of chemical, or rather alchemical ideas and methods of treatment into medicine. The Galenists adhered to the ancient formulas, in which drugs were prescribed, either in substance or in the form of tinctures and extracts, &c.; while the chemists professed to extract from them the essences or quintessences (quinta essentia, the fifth essence, supposed to be particularly pure, as requiring five processes to extract it)—i.e. substances in small bulk, presumed to contain the whole virtues of the original drugs in a state of extreme concentration, or purified from all gross and pernicious or superfluous matter.
There have been numerous editions of Galen's writings, or parts of them; the most accessible, as well as probably the best, is that of C. G. Kühn (20 vols. 1821–33). For a general account of his anatomical and physiological knowledge, see Kidd in vol. vi. of Trans. Provincial Med. and Surg. Assoc. (1837); Daremberg, Des Connaissances de Galien (Paris, 1841); and the epitome in English by J. R. Coxe (Phila. 1846).