This was observed by a stranger who was in the boat with them; he inquired of his neighbour the name of the young man, whose question had put an end to the discourse, and having learned it, set it down in his pocket-book, as it appears, with a malicious design, for in a few days it was the common conversation at Leyden, that Boerhaave had revolted to Spinosa.
It was in vain that his advocates and friends pleaded his learned and unanswerable confutation of all atheistical opinions, and particularly of the system of Spinosa, in his discourse of the distinction between soul and body. Such calumnies are not easily suppressed, when they are once become general. They are kept alive and supported by the malice of bad, and, sometimes, by the zeal of good men, who, though they do not absolutely believe them, think it yet the securest method to keep not only guilty, but suspected men out of publick employments, upon this principle, that the safety of many is to be preferred before the advantage of few.
Boerhaave, finding this formidable opposition raised against his pretensions to ecclesiastical honours or preferments, and even against his design of assuming the character of a divine, thought it neither necessary nor prudent to struggle with the torrent of popular prejudice, as he was equally qualified for a profession, not, indeed, of equal dignity or importance, but which must, undoubtedly, claim the second place among those which are of the greatest benefit to mankind.
He, therefore, applied himself to his medical studies with new ardour and alacrity, reviewed all his former observations and inquiries, and was continually employed in making new acquisitions.
Having now qualified himself for the practice of physick, he began to visit patients, but without that encouragement which others, not equally deserving, have sometimes met with. His business was, at first, not great, and his circumstances by no means easy; but still, superiour to any discouragement, he continued his search after knowledge, and determined that prosperity, if ever he was to enjoy it, should be the consequence not of mean art, or disingenuous solicitations, but of real merit, and solid learning.
His steady adherence to his resolutions appears yet more plainly from this circumstance: he was, while he yet remained in this unpleasing situation, invited by one of the first favourites of king William the third, to settle at the Hague, upon very advantageous conditions; but declined the offer; for having no ambition but after knowledge, he was desirous of living at liberty, without any restraint upon his looks, his thoughts, or his tongue, and at the utmost distance from all contentions and state-parties. His time was wholly taken up in visiting the sick, studying, ntaking chymical experiments, searching into every part of medicine with the utmost diligence, teaching the mathematicks, and reading the scriptures, and those authors who profess to teach a certain method of loving God [36].
This was his method of living to the year 1701, when he was recommended, by Van Berg, to the university, as a proper person to succeed Drelincurtius in the professorship of physick, and elected, without any solicitations on his part, and almost without his consent, on the 18th of May.
On this occasion, having observed, with grief, that Hippocrates, whom he regarded not only as the father, but as the prince of physicians, was not sufficiently read or esteemed by young students, he pronounced an oration, "de commendando studio Hippocratico;" by which he restored that great author to his just and ancient reputation.
He now began to read publick lectures with great applause, and was prevailed upon, by his audience, to enlarge his original design, and instruct them in chymistry. This he undertook, not only to the great advantage of his pupils, but to the great improvement of the art itself, which had, hitherto, been treated only in a confused and irregular manner, and was little more than a history of particular experiments, not reduced to certain principles, nor connected one with another: this vast chaos he reduced to order, and made that clear and easy, which was before, to the last degree, difficult and obscure.
His reputation now began to bear some proportion to his merit, and extended itself to distant universities; so that, in 1703, the professorship of physick being vacant at Groningen, he was invited thither; but he refused to leave Leyden, and chose to continue his present course of life.