A signal instance of his philosophic moderation is given in the following extract: “For my own part, I am not ambitious of the name of a philosopher, and those who think themselves so, may perhaps consider me blameable on the score of my not having attempted to pierce into those penetralia. Now, writers like these I would just recommend, before they blame others, to try their hand upon some common phenomena of nature that meet us at every turn. For instance, I would fain know why a horse attains its prime at seven, and a man at one-and-twenty years? Why, in the vegetable kingdom, some plants blow in May and others in June? There are numberless questions of this sort. Hence, if many men of consummate wisdom are not ashamed to proclaim their ignorance in these matters, I cannot see why I am to be called in question for doing the same. Etiology is a difficult, and, perhaps, an inexplicable affair; and I choose to keep my hands clear of it. _I am convinced, however, that Nature here, as elsewhere, moves in a regular and orderly manner._” In how wise and firm a tone does Sydenham denounce and demolish the quacks and patent medicine vendors! He considers that any man who can, by any sure line of treatment, or by the application of any specific remedy, control the course of diseases or cut them short, is bound by every possible bond to reveal to the world in general so great a blessing to his race. If he withheld it, he pronounced him a bad citizen and an unwise man; for no good citizen would monopolise for himself a general benefit for his kind, and no wise man would divest himself of the blessing he might reasonably expect from his Maker in contributing to the welfare of the world. Sydenham stands out as a great advocate and champion of Peruvian bark, which, in its modern form of quinine, has justified all that he claimed for it. He is also the founder of the “expectant” treatment. “My chief care,” he says, “in the midst of so much darkness and ignorance, is to wait a little, and proceed very slowly, especially in the use of powerful remedies, in the meantime observing its nature and procedure, and by what means the patient was relieved or injured.”