[3] At the age of eighteen Sydenham attended Magdalen Hall, Oxford; after a short period his college studies appear to have been interrupted, and he served for a time as an officer in the Parliamentarian army during the Civil War.

[6] In 1663 he passed the examinations of the College of Physicians for their licence to practice in Westminster and 6 miles round; but it is probable that he had been settled in London for some time before that.

In a letter to John Mapletoft he refers to a class of detractors "qui vitio statim vertunt si quis novi aliquid, ab illis non-prius dictum vel etiam inauditum, in medium proferat" ("Who by a technicality suddenly turn if something is new, if someone should disclose something not previously said or heard"); and in a letter to Robert Boyle, written the year before his death (and the only authentic specimen of his English composition that remains), he says, "I have the happiness of curing my patients, at least of having it said concerning me that few miscarry under me; but [I] cannot brag of my correspondency with some other of my faculty ....

Though yet, in taken fire at my attempts to reduce practice to a greater easiness, plainness, and in the meantime letting the mountebank at Charing Cross pass unrailed at, they contradict themselves, and would make the world believe I may prove more considerable than they would have me."

In 1682 he published another Dissertatio epistolaris (Dissertation on the Letters), on the treatment of confluent smallpox and on hysteria, addressed to Dr William Cole of Worcester.

His last completed work, Processus integri (The Process of Healing), is an outline sketch of pathology and practice; twenty copies of it were printed in 1692, and, being a compendium, it has been republished more often both in England and in other countries than any other of his writings separately.

But the attitude of the academical medicine of the day is doubtless indicated in Martin Lister's use of the term sectaries for Sydenham and his admirers, at a time (1694) when the leader had been dead five years.

If there were any suspicion that the opposition to him was quite other than political, it would be set at rest by the testimony of Dr Andrew Brown, who went from Scotland to inquire into Sydenham's practice and has incidentally revealed what was commonly thought of it at the time, in his Vindicatory Schedule concerning the New Cure of Fevers.

He is indeed famous because he inaugurated a new method and a better ethics of practice, the worth and diffusive influence of which did not become obvious (except to those who were on the same line with himself, such as Morton) until a good many years afterwards.

[8] A zealous Puritan, "he rejected on religious grounds attempts such as pathological anatomy and microscopic analysis to uncover the hidden causes of disease," arguing that "God only gave man the ability to perceive the outer nature of things with his senses.

Thirdly, and not more beautifully than truly, let him reflect that he has undertaken the care of no mean creature, for, in order that he may estimate the value, the greatness of the human race, the only begotten Son of God became himself a man, and thus ennobled it with his divine dignity, and far more than this, died to redeem it.

[16][17] Sydenham's fundamental idea was to take diseases as they presented themselves in nature and to draw up a complete picture (Krankheitsbild of the Germans) of the objective characters of each.

Chronic diseases, on the other hand, were a depraved state of the humours, mostly due to errors of diet and general manner of life, for which we ourselves were directly accountable.

Hence his famous dictum: "acutos dico, qui ut plurimum Deum habent authorem, sicut chronici ipsos nos" ("I say what hurts, most over which God has authority, just like we ourselves over the chronic").

Sydenham's nosological method is essentially the modern one, except that it lacked the morbid anatomy part, which was first introduced into the natural history of disease by Morgagni nearly a century later.

[18] There had been nothing quite like this in medical literature since the Hippocratic treatise, On Airs, Waters and Places; and there are probably some germs of truth in it still undeveloped, although the modern science of epidemiology has introduced a whole new set of considerations.

After smallpox, the diseases to which he refers most are hysteria and gout, his description of the latter (from the symptoms in his own person) being one of the classical pieces of medical writing.