Thomas Sydenham (1624-89), one of the foremost English physicians of his day, tended to eschew the more theoretical approaches to fevers, preferring instead to base his approach on that of Hippocrates himself: a careful observation of cases leading to judgments on treatment.
Thomas Sydenham, Methodus curandi febres (London, 1676), portrait.
Sydenham’s approach led him to the unenviable conclusion that each individual fever had to be fought as an individual disease, so rapidly did fevers change:‘But this I am sure of by many Observations, that the abovemention’d species of Diseases, especially continual Fevers, do very much differ; for that method which is successful one year, may perhaps be destructive another. And when I had once happily met with a method of Cure, which this or that kind of Fever did particularly require, I scarce ever fail’d of Success, respect being had to the Temperament, and Age, and the like, till the Species was extinct; but when a new one did arise, I was in doubt which way I should steer, so as to be serviceable to my Patient; and unless I took great Care, and used my utmost Endeavours, I could scarce help, but that one or two of those I had first in hand would be in great danger, till I had found out the Genius of the Disease, and then I could again proceed readily to the curing of it.
Sydenham, The Whole Works (London, 1696),pp 4-6.
Sydenham’s works were translated into English by John Pechey, whose own Collections of acute diseases (London, 1691) was also collected by Worth. Pechey, like his hero, was at pains to point to the seasonal nature of fever epidemics:‘…We must remember that in Autumn 1677, Intermittent Fevers first advanc’d and increas’d dayly, and were Epidemic till they came to their state; afterwards they gradually decreas’d and so rarely appear’d the last Years of this Constitution, that they cou’d not be counted Epidemical; and on this account we must likewise take notice that the two last Years of the Constitution now going off, had two very severe Winters, especially the last save one, viz the Year 1683, in which the season was so extreamly cold, that no Man living ever saw the like, as to the intense degree of cold, and the long time it held….
Pechey, Collections of acute diseases (London, 1691),pp 65-7.
But if Sydenham was content to avoid the more theoretical discussion of what exactly caused fever in favour of development of methods of treatment, other physicians focused on the genesis of the disease. Edward Worth’s copy of Sir Richard Blackmore’s A treatise upon the small-pox (London, 1732), contains a typical discussion of different kinds of fevers and their causes:‘A Fever is an inordinate Elevation of the oyly or fiery Parts of the Blood, by which the balance of Power between the active and governing Principles being broken, a great Tumult and Disorder arises in the animal Oeconomy, attended with immoderate heat and Thirst, too high and often too swift a Pulse, Head-ake, and sickness of Stomach, and is either original in the Blood and Humours of the Body, or secondary and derived from some other previous Distemper. Of the first sort are all Fevers call’d acute, produced by the Admission of noxious Matter into the Blood, while the solid Parts are sound and entire: The Secondary are but an Effect or Symptom of some other Disease, of which Kind are hectick, scorbutick, wandring and white Fevers, which proceed from some antecedent Distemper, and that chiefly in one of the Bowels, and these being slow and lingering, and protracted to a considerable space of Time, are therefore called Chronical.
As his discussion makes clear, the dominant theory of causation for Blackmore was still humoral, but, as Sigal (1978) has pointed out, William Harvey’s theory of the circulation of the blood had issued a challenge to humoral based medicine. Other writers in Worth’s collection of fever texts took up this challenge and foremost among them was Thomas Willis (1621-75), an iatrochemist who sought to highlight the role chemistry might play in the treatment of disease.
Thomas Willis, Diatribæ duæ medico-philosophicæ (London, 1659), title page.
For Willis, causation was based on a theory of fermentation of the blood, one natural, the other ‘preternatural’. Dividing fevers into ‘intermittent fevers’, ‘continual fevers’ and ‘malignant fevers’, he advocated a host of different treatments, predominantly of a chemical nature. Later commentators (also collected by Worth), such as George Cheyne (1671–1743), adopted a more mechanistic approach, strongly influenced by the works of Giovanni Alfonso Borelli (1608-1679) and Lorenzo Bellini (1643-1704), authors whose works were likewise collected by Worth.