his constitution for intemperance. When about thirty years of age, having taken the degree of M. D. he repaired to London, and there commenced practice as a physician. It affords a curious picture of the times, that he found it necessary to become a frequenter of taverns in order to get into practice. His cheerful temper, and vivacious conversation soon rendered him the favourite of the other gentlemen who frequented those places; he "grew daily," he says, " in bulk, and in friendship with those gay men, and their acquaintances." But this could not last long. He soon became excessively fat, short-winded, and lethargic, and being further admonished by an attack of vertigo, nearly approaching to apoplexy, he was obliged to abandon that style of life altogether.
Previous to this period, he had written, at the request of Dr Pitcaime, "A new Theory of Acute and Slow continued Fevers; wherein, besides the appearances of such, and the manner of their cure, occasionally, the structure of the glands, and the Manner and Laws of Secretion, the operation of purgative, vomitive, and mercurial medicines, are mechanically explained." Dr Pitcairne had wished to write such a work himself, in order to overthrow the opposing theories of some of his brethren, but was prevented from doing so by his constant application to practice, and therefore desired Dr Cheyne to undertake the task in his place. The work was hastily produced, and, though it was favourably received, the author never thought it worthy of receiving his name. The next work of Dr Cheyne was entitled, "Fluxionum Methodus Inversasive quantitatum fluentium leges generales." Like many men who are eminent in one professional branch of knowledge, he was anxious to display an amateur's accomplishment in another; and hence this attempt at throwing light upon the mysteries of abstract geometry. In later life, he had the candour to say of this work, that it was "brought forth in ambition, and brought up in vanity. There are some things in it," he adds, "tolerable for the time, when the methods of quadratures, the mensuration of ratios, and transformation of curves into those of other kinds, were not advanced to such heights as they now are. But it is a long time since I was forced to forego these barren and airy studies for more substantial and commodious speculations: indulging and rioting in these so exquisitely bewitching contemplations being only proper to public professors, and those who are under no outward necessities. Besides, to own a great but grievous truth, though they may quicken and sharpen the invention, strengthen and extend the imagination, improve and refine the reasoning faculty, and are of use both in the necessary and luxurious refinement of mechanical arts; yet, having no tendency to rectify the will, sweeten the temper, or mend the heart, they often leave a stiffness, positiveness, and sufficiency on weak minds, much more pernicious to society, and the interests of the great ends of our being, than all the advantages they can bring can recompense."
On finding his health so materially affected by intemperance, Dr Cheyne left off eating suppers entirely, and in his other meals took only a little animal food, and hardly any fermented liquor. He informs us, that being now confined to the penitential solitude of a sick chamber, he had occasion to experience the faithlessness of all friendship formed on the principle of a common taste for sensual indulgences. His boon companions, even those who had been particularly obliged to him, left him like the stricken deer, to bewail his own unhappy condition; "so that at last," says the doctor, "I was forced into the country alone, reduced to the state of cardinal Wolsey, when he said, 'if he had served his Maker as faithfully and warmly as he had his prince, he would not have forsaken him in that extremity;' and so will every one find, when union and friendship is not founded on solid virtue, and in conformity to theMivine order,
