Erasistrătus in Harpers Dictionary of Classical Antiquities

（Ἐρασίστρατος). A physician of Iulis, in the island of Ceos, and grandson of Aristotle by a daughter of this philosopher. After having frequented the schools of Chrysippus, Metrodorus, and Theophrastus, he passed some time at the court of Seleucus Nicator, where he gained great reputation by discovering the secret malady which preyed upon the young Antiochus, the son of the king, who was in love with his stepmother, Queen Stratonicé (Appian. Bell. Syr. 59). It was at Alexandria, however, that he principally practised. At last he refused altogether to visit the sick, and devoted himself entirely to the study of anatomy. The branches of this study which are indebted to him for new discoveries are, among others, the doctrine of the functions of the brain and that of the nervous system. He immortalized himself by the discovery of the viae lacteae; and he would seem to have come very near to that of the circulation of the blood. Comparative anatomy furnished him with the means of describing the brain much better than had ever been done before him. He also distinguished and gave names to the auricles of the heart (Galen, De Dogm. Hipp. et Plat. vii.; De Usu Part. viii.; De Administr. Anat. vii.; An Sanguis, etc.). A singular doctrine of Erasistratus is that of the πνεῦμα, or the spiritual substance which, according to him, fills the arteries, which we inhale in respiration, which from the lungs makes its way into the arteries, and then becomes the vital principle of the human system. As long as this spirit moves about in the arteries, and the blood in the veins, man enjoys health; but when, from some cause or other, the veins become contracted, the blood then spreads into the arteries and becomes the source of maladies; it produces fever when it enters into some noble part or into the great artery, and inflammations when it is found in the less noble parts or in the extremities of the arteries. Erasistratus rejected entirely blood-letting, as well as cathartics; he supplied their place with dieting, tepid bathing, vomiting, and exercise. In general, he was attached to simple remedies; he recognized what was subsequently termed idiosyncrasy, or the peculiar constitution of different individuals, which makes the same remedy act differently on different persons. A few fragments of the writings of Erasistratus have been preserved by Galen.

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