Medicine: Blood

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In the jaunty but therapeutically casual days of the 17th century two men often sat late over their wine cups. The one was dressed in silks and at his side a slim sword swung. The other's garb was black, but his eyes gleamed in candlelight. Sword-swinger was England's Charles I; the eyes gleamed in the head of Dr. William Harvey, no ordinary leech. Last week 100 chosen doctors from the world over gathered in London to celebrate the 300th anniversary of the royal leech's book* which first told the world that blood completes a circle through the body. The 100 doctors wore full dress and all their decorations; they were received at Buckingham Palace by England's George V.

Charles liked his leech. The man had a visible vitality which often translated itself into swift rages and quick passes with the dagger at his side. It is not recorded that Dr. Harvey's blade penetrated anything more eventful than frogs, birds and an occasional cadaver. But these things it penetrated so shrewdly that the doctor had an idea. It was not, solely, his idea, but rather an astounding improvement on the theories of his teacher, Dr. Hieronymus Fabricius of Aquapendente. This doctor lectured at the school of physic at Padua, Italy, and the inquisitively inclined can still visit the great carved room where Dr. Harvey first heard from Dr. Fabricius of the valves he had discovered in the veins. But Dr. Fabricius was foggy on one point. In common with other great medical minds of his time he believed blood oscillated back and forth in the veins and arteries. This theory the sharp eyed pupil doubted.

He pursued his doubts to certainty through the bodies of innumerable lobsters, oysters, slugs, fishes, frogs, serpents, pigs, dogs, chicks.

His theories crystallized into lectures. His distinguished friends urged him to publish, his scientific spirit urged him to accumulate more data. In 1628 a slim volume of 72 pages with two plates of diagrams came out under his name—72 pages of clear, logical, dignified exposition in which the whole existing theory of the blood was demolished. Homer, Aristotle, Plato, every village barber who had ever breathed a vein had known that the blood moved but until the hawkeyed Harvey, no one knew:

That the heart is a muscular organ squeezing the blood forth when it contracts, resting quietly when it relaxes or swells (a complete contradiction of the idea prevailing in the days of the Stuarts). That the arteries carry bright scarlet blood, which has taken up air in its passage through the lungs, to every part of the body.

That the veins carry dark impure blood back to the heart from which it is sent to the lungs, purified, brightened by a fresh supply of air.

That the brilliant red blood in the arteries is exactly the same as the dark blue blood of the veins, the difference in color being due to difference in gas content. That there is no to and fro undulation, but a constant circuit of blood from the heart, through the distant parts of the body, back to the heart.