Harvey, Sydenham and Disease Treatment c1600-1750

A Long Slow Century

Between Vesalius’s anatomy in 1543 and Jenner’s vaccination in 1796 lies a quarter of a millennium that students often skip over. They shouldn’t. This is when British medicine became more organised, more clinically observant, and more separated by trade — even though the underlying theory of disease barely budged. The 17th and 18th centuries are the gap between ‘Galen has been challenged on the page’ and ‘treatment has actually changed’. Four developments anchor the period: William Harvey on circulation, Thomas Sydenham on clinical observation, the rise of voluntary hospitals, and John Hunter’s scientific approach to surgery.

William Harvey and the Circulation

William Harvey was an English physician trained at Cambridge and Padua — the same school where Vesalius had worked. He served as personal physician to James I and Charles I. By repeatedly dissecting human and animal bodies, and by simple experiments on living patients (squeezing arm veins, tracking valves), Harvey worked out that blood does not seep slowly through the body but moves in a continuous loop. The heart, he showed, is a muscular pump.

This overturned Galen on a fundamental point. Galen had taught that the liver made blood, the heart warmed it, and the body consumed it. Harvey’s circulation made nonsense of bleeding as a treatment — if blood is circulating, removing pints of it weakens rather than rebalances the patient. Yet bleeding remained a standard treatment for over 200 years after Harvey’s book. The discovery and the application were not connected.

Why Did It Take So Long to Change Treatment?

Three reasons. Harvey could not explain why blood circulated — he had no microscope to see capillaries (those came in 1661 with Marcello Malpighi). He had no rival theory of disease to replace humours, so doctors continued bleeding for want of an alternative. And the medical profession was conservative: Galen still appeared on university reading lists into the 19th century. The first successful human-to-human blood transfusion was not until 1818, by James Blundell at Guy’s. Circulation theory finally became clinically useful only when later science caught up.

Thomas Sydenham, the ‘English Hippocrates’

Thomas Sydenham never went to medical school in the standard sense — he served on the Parliamentary side in the Civil War. When he set up practice in London he made a deliberate choice: ignore the textbooks and watch the patient. Sydenham was the first British physician in centuries to insist that diseases were specific entities with specific patterns, rather than generic humour imbalances. He distinguished scarlet fever from measles, described gout from his own painful experience, and used cinchona bark (containing quinine) for fevers we now call malaria. His approach earned him the nickname ‘the English Hippocrates’.

The Great Plague of 1665

A reminder of how little had changed: when the Great Plague hit London in 1665 it killed roughly 100,000 people, about a quarter of the city’s population. Responses were similar to 1348 — quarantine, plague doctors in beaked masks stuffed with herbs (treating miasma), prayers, and royal proclamations to clean the streets. The Great Fire of London in 1666 destroyed many infested buildings; whether or not this ended the plague (and historians still debate it), no theoretical advance had been made on causation. Theory and practice still ran on parallel tracks.

The Rise of Voluntary Hospitals

The 18th century is when British hospitals began to look modern. With monasteries gone since Henry VIII’s dissolution (1536-40), wealthy individuals and subscribers funded new voluntary hospitals. Westminster Hospital opened in 1719, Guy’s in 1724, the London in 1740. These institutions still mostly cared for the poor — the wealthy were treated at home — but they began to function as places of treatment, not just hospitality. Surgeons and physicians attached to these hospitals taught medical students at the bedside, a model that would become standard in the 19th century.

The same century saw the trades separate. Surgeons split formally from barbers in 1745, becoming a recognised profession with their own Royal College in 1800. Physicians remained at the top, dispensing medicine, while surgeons gained respectability through scientific training. The hierarchy that had defined medieval medicine was finally cracking.

John Hunter and Scientific Surgery

John Hunter (1728-1793) was a Scottish surgeon working in London who pushed surgery toward science. He insisted that surgery should be based on observation, dissection and experiment — not just classical authority. Hunter built up an enormous collection of anatomical specimens (now in the Royal College of Surgeons), taught hundreds of students at his St George’s Hospital classes, and ran experiments on himself and others.