It frequently happens in the West Indies that intermittent fevers are so obstinate as to resist the common means of cure by the Peruvian bark; so that these complaints become extremely distressing to the medical practitioner as well as to the patient. Indeed this was a difficulty that occurred so often, that I was sometimes tempted to think, either that the great reputation of this medicine is not so well founded as is commonly believed, or that the bark generally in use in these times is not of so good a quality as that employed by the physicians who first established its character. But, in the first place, the experience upon which its reputation was first built was in a temperate climate, where very few agues are found to resist it when properly administered. In the next place, there is reason to believe that, in fact, the medicine itself now commonly in use is not equally powerful with what was first employed; and a species of it, called the Red Peruvian Bark, has lately been discovered, or rather, perhaps, revived, which is certainly of a superior quality, and has been found to cure intermittents in which the common sort had failed[110]. However this may be, it is an undoubted fact that obstinate agues are much more frequent in the West Indies than in Europe; and something to supply the insufficiency of the bark seemed to be a _desideratum_. I was informed by Dr. Hendy, of Barbadoes, that he had found the flowers of zinc to answer in cases of intermittent fever, in which even the bark and every other remedy and mode of treatment had failed. It was found very successful in the like cases, both in my own trials at the hospitals, and by the surgeons of the men of war to whom I recommended the use of it. In order to judge what may be expected from it, I shall give a specimen of its success in some cases, at the hospital at St. Lucia, of which I kept an accurate account, in the months of February and March, 1783. About the time the fleet arrived there, six cases of intermittent fevers were sent to the hospital from different ships. One was of six weeks continuance, and had been some times of the tertian, sometimes of the quartan type. Two were quartans; one of which was of two months, the other of eight months duration. Two were regular tertians; of which one had only had two fits, but was a relapse after a week’s exemption from an attack of several weeks. The other was of three months continuance, attended with an eruption on the hands and arms. The sixth case was a quotidian of three weeks, attended with a cough of the same standing, and joined with sea scurvy.