The Sydenham-Boyle theory of morbific particles.

NOT LONG after the sense of pleasure at the privilege of being invited to give this Sydenham Lecture, I found myself troubled by my own attitude to what I knew of Sydenham. Like many others I had been introduced to Sydenham as the English Hippocrates, the clinical observer untrammelled by theory, and turning to Sydenham's Medical observations I had expected to find something similar to the clinical works of Hippocrates. This expectation was rudely shattered by its opening chapters, for instead of finding clinical descriptions I found a mass of speculative theoretical statements about "morbific particles", "peccant matter", etc., in disease. This was not what I had expected from this great clinician who not only took Bacon's inductive principles as his guide but repeatedly protested loudly against medical speculation. How did our English Hippocrates reconcile so unhippocratic an account of disease with his brilliant clinical descriptions? Here was my problem; and the invitation to give this Sydenham Lecture challenged me to solve it. Today I would like to define the problem further and offer my solution to you. First I must say that I am glad to find that I am not alone in being troubled by Sydenham's theoretical speculations. As long ago as 1797 James Currie, a fine clinician, who used the clinical thermometer in cases of fever, wrote,' "That he [Sydenham] recorded symptoms with great accuracy; and that he was a more cautious reasoner than his predecessors or contemporaries are facts that are indisputable. But though he affected not to theorize he was a theorist in every page of his works." Turning to more recent times I find that that distinguished contemporary medical historian, Oswei Temkin,2 has shared this discomfort by comparing Hippocrates' works on Epidemics with our English Hippocrates' Medical observations, so displaying an unexpectedly marked contrast between their very different concepts of disease. Turning to Sydenham's works themselves, I would first draw your attention to the fact that Sydenham dedicated his Methodus curandifebres of 1666 to Robert Boyle, acknowledging his influence in the undertaking particularly, since Boyle had accompanied him in visiting the sick. It is relevant to my theme to note that Boyle when in London lived with his sister, Lady Ranelagh, next door to Sydenham in Pall Mall. This intimate and neighbourly friendship with Boyle lasted for the rest of Sydenham's life. In my opinion, it relates significantly to Sydenham's medical theory. I shall return to it later.