Chicago (2023) h/b 320pp £41.99 (ISBN 9780226 828770)

W. explains the ways in which analogies using the tools and machines of the time informed explanations of bodily functions, and to some degree health and disease. The Hippocratic texts provide a simple example: wool, which both absorbs and expels moisture, was used to explain why female flesh was so soft.

Plato’s Timaeus is the first text to use the term organon, though it is not tools that he uses as an analogy for the internal organs and tools, but rather objects and structures, only vaguely connected to mechanisms, designed primarily to demonstrate the Platonic rationality of the Divine Craftsman. For example, the heart is a ‘guard house’, to protect the emotional part of the soul. The lungs are sponge-like, able to receive air and drink to cool the heart, when anger makes it hot, and to cushion the heart and protect it from injury, when rage makes it leap up in the chest. Plato also makes use of an analogy produced by Empedocles who saw how the vessel known as a clepsydra, flat-bottomed with multiple perforations on the base and a small opening in the hollow handle above, could explain how breathing worked. As this vessel was submerged in water it made a ‘breathing’ noise as air was forced out of the small orifice in the handle, and when lifted from the water, the water within escaping from the base again producing a breathing-like noise as air entered the vessel. A great deal is made of this, though the analogy does not quite work because the clepsydra is of fixed volume, while the rise and fall of the chest indicate changes in volume. But it is a start.

Aristotle, almost inevitably, introduced a level of sophistication into the argument by marrying form (bodily mechanisms) and function (their purpose) to organise the body into a system fitted for the maintenance of life, thus inventing the concept of physiology. He was the first to use the analogy with bellows for the lungs: for him, respiration was the consequence of hot air escaping from the lungs and cool air entering to take up its place, where it was heated up by the hot blood.

Aristotle, then, thought blood was concocted by the heart, acting as a sort of furnace and he connects the actions of the heart with throbbing, beating (likened to boiling, producing a pulse) and breathing. But it is to modern anatomists surprising that he identified three chambers to the heart. Aristotle was a clever anatomist and shrewd observer. It would appear, modern anatomists agree, that he regarded the right atrium as a part of the venous system, and not of the heart. His right ventricle was the modern right ventricle, his left ventricle our left atrium, and his middle ventricle our left ventricle There may be some confusion of terminology in the text as it is stated that the largest chamber in the heart is the right ventricle when it is in fact the left/middle. (I note that reptiles and amphibians have a genuinely three -chambered heart. Was Aristotle thinking of those?)

The emergence of water pumps and pneumatic devices coincides with Erasistratus’ observations in the first half of the third century BC concerning the heart and the kidneys. He rejects the idea of heat expelling the blood into the body (not circulating, of course) and proposes that the heart does so, acting as a pump. He observed the presence of valves in the heart, and suggested their purpose was to prevent the blood flowing back. It is worth noting that the four-humour theory of disease was flatly rejected by Erasistratus. It took the modern world over a thousand years to see that he was right to do so.

By the time we have reached Galen we are in an age of public demonstrations of anatomy for education and entertainment. Descriptions of anatomy are more accurate, but still contain errors. Those who have performed a post-mortem examination will know that as soon as the chest is opened, a healthy lung collapses; thus air appears to be present within the chest, between the partly collapsed lung and the chest wall. I suspect that this may in part explain the persistence of the idea that pneuma circulates in the arteries, preventing doctors coming up with the idea of the circulation of blood.

However that may be, Galen’s copious writings (2.6 million words, despite the loss of much of his work) are full of analogies for bodily functions. He compares tendons to puppet strings and joints to hinges and observes that the hand is a tool for tools and believes that we walk upright in order to use our hands. He also devised many specialized tools for surgical use, including the impressive—even today—box splint, used to keep the fractured parts of limbs in place until they properly set.

This is a complex subject and W. has to go into detail to expound it. While the ancients’ simple mechanical analogies are easy to grasp, their analogies with, e.g. pumps and the heart are less successful, not because of the inappropriateness of the analogy, but through a combination of faulty understanding of the body’s workings and a failure to explore the analogy as critically as possible.

W. ends by pointing out how successful the analogy with tools and mechanisms has been both in advancing understanding of how the body functions, and as a spur to inventing machines that would do the work of the body e.g. iron lungs.

This book will appeal to the classicist interested in original sources and interpretation of the Greek, to the medical historian, and any doctor with an interest in medical history.

David Smith FRCPath.