And addressing myself to learned men as a physician, I shall treat of the health of studious men; and here again I must request your indulgence: _Dira per incautum serpunt contagia vulgus._ _A dire contagion through the vulgar spreads._ But whilst I was hurried about to attend a crowd of patients, I had no leisure to polish my work; therefore I have without method thrown together my thoughts and observations on this useful topic. It is an old complaint, that study, though essentially necessary to the mind, is hurtful to the body; and CELSUS has intimated the necessity of a remedy. Those that are of weak constitutions, says he, as most studious men are, should take greater care than others, that what is impaired by application to their studies may be repair’d by attention to their constitutions. And PLUTARCH, an admirable judge of what is right and becoming, declares it to be a shame, that the learned should spend days and nights in useless investigations, and at the same time neglect the art of preserving their health; being, doubtless, ignorant that the healing science was formerly look’d upon as a part of wisdom, and that those chiefly requir’d medical assistance, who have impair’d their bodily strength by anxious thought and watchfulness. There are two principal sources, from whence all the sufferings of the studious flow; the constant exercise and application of the mind, and the continual rest of the body; for they are as indolent in body, as they are busy and active in mind. By enumerating the ills, that arise from both causes, a dreadful crop of diseases will be display’d. Let metaphysicians bewilder themselves in inquiries, how the mind governs the body, and is govern’d by the latter in its turn; physicians, descending to considerations of less importance, but of greater certainty, perhaps, and little sollicitous about the causes of this mutual government, and but confining their inquiries to phænomena, know by experience, that certain emotions of the mind necessarily arise from certain conditions of the body, and that by particular emotions in the mind particular changes are unavoidably produc’d in the body, and that whilst the mind thinks, some part of the brain is stretch’d. We make no other inquiry; it would be of no use to know any thing farther.