this vaft chaos he reduced to order, and made that clear and easy which was before to the laft degree dif ficult and obfcure.

His reputation began now to bear fome proportion to his merit, and extended itself to diftant univerfities; fo that, in 1703, the profefforfhip of phyfick being vacant at Groningen, he was invited thither; but he refused to leave Leyden, and chofe to continue his prefent course of life.

This invitation and refufal being related to the governors of the university of Leyden, they had fo grateful a sense of his regard for them, that they immediately voted an honorary increase of his falary, and promised him the first profefforship that should be

vacant.

On this occafion he pronounced an oration upon the use of mechanicks in the science of phyfick, in which he endeavoured to recommend a rational and mathematical enquiry into the causes of diseases, and the structure of bodies; and to fhew the follies and weakneffes of the jargon introduced by Paracelfus, Helmont, and other chemical enthusiasts, who have obtruded upon the world the moft airy dreams, and, instead of enlightening their readers with explications of nature, have darkened the plaineft appearances, and bewildered mankind in error and obscurity.

Boerhaave had now for nine years read phyfical lectures, but without the title or dignity of a profeffor, when, by the death of profeffor Hotten, the profefforship of phyfick and botany fell to him of course.

On this occafion he afferted the fimplicity and facility of the fcience of phyfick, in oppofition to those

that

that think obfcurity contributes to the dignity of learning, and that to be admired it is neceffary not to be understood.

His profeffion of botany made it part of his duty to fuperintend the phyfical garden, which improved fo much by the immenfe number of new plants which he procured, that it was enlarged to twice its original

extent.

In 1714 he was defervedly advanced to the highest dignities of the univerfity, and in the fame year made phyfician of St. Auguftin's hofpital in Leyden, into which the students are admitted twice a week, to learn the practice of phyfick.

This was of equal advantage to the fick and to the ftudents, for the fuccefs of his practice was the best demonftration of the foundness of his principles.

When he laid down his office of governor of the univerfity in 1715, he made an oration upon the fubject of "attaining to certainty in natural philofophy;" in which he declares, in the ftrongest terms, in favour of experimental knowledge, and reflects with just feverity upon thofe arrogant philofophers, who are too easily difgufted with the flow methods of obtaining true notions by frequent experiments, and who, poffeft with too high an opinion of their own abilities, rather chufe to confult their own imaginations, than enquire into nature, and are better pleased with the charming amufement of forming hypothefes, than the toilfome drudgery of making obfervations.

The emptiness and uncertainty of all those systems, whether venerable for their antiquity or agreeable for their novelty, he has evidently fhewn; and not only

declared, but proved, that we are entirely ignorant of the principles of things, and that all the knowledge we have is of fuch qualities alone as are discoverable by experience, or fuch as may be deduced from them by mathematical demonstration.

This difcourfe, filled as it was with piety, and a true fenfe of the greatnefs of the Supreme Being, and the incomprehenfibility of his works, gave fuch offence to a profeffor of Franeker, who profeffed the utmost esteem for Des Cartes, and confidered his principles as the bulwark of orthodoxy, that he appeared in vindication of his darling author, and spoke of the injury done him with the utmost vehemence, declaring little less than that the Cartefian fyftem and the Chriftian muft inevitably ftand and fall together, and that to fay we were ignorant of the principles of things, was not only to enlift among the Sceptics, but fink into Atheism itself.

So far can prejudice darken the understanding, as to make it confider precarious fyftems as the chief fupport of facred and unvariable truth.

This treatment of Boerhaave was fo far refented by the governors of his univerfity, that they procured from Franeker a recantation of the invective that had been thrown out against him; this was not only complied with, but offers were made him of more ample fatisfaction; to which he returned an anfwer not lefs to his honour than the victory he gained, "that he "fhould think himfelf fufficiently compenfated, if "his adverfary received no farther molestation on his "account."

So far was this weak and injudicious attack from fhaking a reputation not cafually raised by fashion or

caprice,

caprice, but founded upon folid merit, that the fame year his correfpondence was defired upon Botany and Natural Philofophy by the Academy of Sciences at Paris, of which he was, upon the death of count Marfigli, in the year 1728, elected a member.

Nor were the French the only nation by which this great man was courted and diftinguished, for two years after he was elected fellow of our Royal Society.

It cannot be doubted but, thus careffed and honoured with the highest and most publick marks of efteem by other nations, he became more celebrated in the university; for Boerhaave was not one of those learned men, of whom the world has seen too many, that difgrace their studies by their vices, and by unaccountable weakneffes make themselves ridiculous at home, while their writings procure them the veneration of distant countries, where their learning is known, but not their follies.

Not that his countrymen can be charged with being infenfible of his excellencies till other nations taught them to admire him; for in 1718 he was chofen to fucceed Le Mort in the profefforship of chemistry; on which occafion he pronounced an oration "De Chemia errores fuos expurgante," in which he treated that science with an elegance of ftyle not often to be found in chemical writers, who feem generally to have affected not only a barbarous, but unintelligible phrafe, and to have, like the Pythagoreans of old, wrapt up their fecrets in fymbols and ænigmatical expreffions, either because they believed that mankind would reverence moft what they leaft understood, or

because

because they wrote not from benevolence but vanity, and were defirous to be praised for their knowledge, though they could not prevail upon themselves to communicate it.

In 1722, his course both of lectures and practice was interrupted by the gout, which, as he relates it in his fpeech after his recovery, he brought upon himself, by an imprudent confidence in the ftrength of his own conftitution, and by tranfgreffing those rules which he had a thousand times inculcated to his pupils and acquaintance. Rifing in the morning before day, hei went immediately, hot and fweating, from his bed into the open air, and expofed himself to the cold dews.

The hiftory of his illness can hardly be read without horror: he was for five months confined to his bed, where he lay upon his back without daring to attempt the leaft motion, because any effort renewed his torments, which were fo exquifite, that he was at length not only deprived of motion, but of fenfe. Here Art was at a stand, nothing could be attempted, because nothing could be propofed with the leaft profpect of fuccefs. At length having, in the fixth month of his illness, obtained fome remiffion, he took fimple medicines in large quantities, and at length wonderfully recovered.

His recovery, fo much defired, and fo unexpected, was celebrated on Jan. 11, 1723, when he opened his fchool again with general joy and publick illumi

nations.

"Succos preffos bibit Nofter herbarum Cichoreæ, Endiviæ, Fumariæ, Nafturtii aquatici, Veronica aquatica latifolia, copia ingenti; fimul deglutiens abundantiffimè gummi ferulacea Afiatica." Orig. Edit.