Peter Mere Latham, born in 1789, was appointed physician to the Middlesex Hospital at the age of 26 and elected fellow of the Royal College of Physicians three years later. He joined St Bartholomew’s in 1827 and became physician extraordinary to Queen Victoria in 1837. His writings, published between 1828 and 1846, have long ranked as medical classics and are now patiently waiting to be made available on the internet. They were favourites with William Bean, former editor of the Archives of Internal Medicine, who admired their wisdom and stately elegant style and who in 1962 published their best parts as a collection of aphorisms.

In these aphorisms we find some immutable truths. We should not think ourselves wiser than we are. Nothing is more captivating than new knowledge. We learn more from our patients than from books. We learn by doing, not by reading or being fascinated by popular lecturers; and lectures are a temptation to the more contemplative mind. Medical books are needlessly “complex and multifarious.” It takes more time and trouble to pull down a falsehood than to build up a new truth. Diagnosis is sometimes easy, sometimes difficult, sometimes impossible. Poisons and medicines are often the same substances, given with different intents. The best physicians learn their craft by caring for the poor. Most doctors are not very exact in the use of their language. Considering the many possibilities of error, it would be strange indeed if we were always right. Some patients of delicate and nervous disposition exaggerate their symptoms and are troublesome to deal with, difficult to understand, and apt to deceive both the doctor and themselves. With students one should strive not to teach but encourage them to learn.

Latham believed that knowledge can be an encumbrance as well as a help. With Aristotle, he thought that one should not treat a subject with more precision than its nature admits. He thought the practice of medicine was jostled by quacks on one side and science on the other. He perceived that professions, then as now, have a way of glorifying themselves by setting forth a vast array of preparatory studies, pretending that these were indispensable in fitting a person for the simple exercise of the practical duties he or she will be expected to carry out.

At the time when Latham wrote there were no antibiotics or anaesthesia, germs were not known to cause disease, typhoid was confused with typhus and was merely part of “fevers,” and doctors had little to give besides opium, mercury, and themselves. Hence the modern reader’s difficulty and discomfort in trying to determine what is still relevant in an age where experience is trumped by multinational trials, bedside medicine by the laboratory, and clinical wisdom by government directives and administrative pronouncements.

Reproduced with permission from BMJ 2008;337:a1742