Page:The Harveian oration 1911.djvu/12

THE TREATMENT OF CONSUMPTION 4

Erasistratus and Herophilus, further amplified his system, and explained that while the veins carried blood from the heart to the members, the arteries carried a subtle kind of air or spirit. According to Dr. Pye-Smith’s admirable epitome of the subject, only two changes had been made, for the practical physician, in this theory of the circulation between the Christian era and the sixteenth century.

Galen had discovered that the arteries were not, as their name implies, merely air tubes, but that they contained blood as well as vital air or spirit, and it had been gradually ascertained that the nerves (veipa) which arose from the brain and conveyed animal spirits to the body were different from the tendons and sinews (vedpa) which attach themselves to bones.

The state of knowledge may be summarized as follows:—

(1) At the time of Linacre (1524) physicians knew that the blood was not stagnant in the body, for this had been apparent even to the ancient augurs when they inspected the entrails of a victim and, as Dr. Pye-Smith remarked, to every village barber who “ breathed” a vein ; but no one had a conception of a continuous stream returning to its source—.e., of a circulation in the true sense of the word—either in the system or lungs, for they were only cognisant of some slow and irregular movement of the blood.

(2) Physicians, before Harvey, supposed that