When Bishop Berkeley visited the illustrious Malebranche at Paris, he found him in his cell, cooking in a small pipkin a medicine for an inflammation of the lungs, from which he was suffering; and the disease, being unfortunately aggravated by the vehemence of their discussion, or the contents of the pipkin, carried him off in the course of a few days.  Berkeley himself afforded a remarkable illustration of a truth which has long been known to the members of one of the learned professions, namely, that no amount of talent, or of acquirements in other departments, can rescue from lamentable folly those who, without something of the requisite preparation, undertake to experiment with nostrums upon themselves and their neighbors.  The exalted character of Berkeley is thus drawn by Sir James Mackintosh:  Ancient learning, exact science, polished society, modern literature, and the fine arts, contributed to adorn and enrich the mind of this accomplished man.  All his contemporaries agreed with the satirist in ascribing

   “‘To Berkeley every virtue under heaven.’

“Even the discerning, fastidious, and turbulent Atterbury said, after an interview with him, ’So much understanding, so much knowledge, so much innocence, and such humility, I did not think had been the portion of any but angels, till I saw this gentleman.’”

But among the writings of this great and good man is an Essay of the most curious character, illustrating his weakness upon the point in question, and entitled, “Siris, a Chain of Philosophical Reflections and Inquiries concerning the Virtues of tar water, and divers other Subjects,”—­an essay which begins with a recipe for his favorite fluid, and slides by gentle gradations into an examination of the sublimest doctrines of Plato.  To show how far a man of honesty and benevolence, and with a mind of singular acuteness and depth, may be run away with by a favorite notion on a subject which his habits and education do not fit him to investigate, I shall give a short account of this Essay, merely stating that as all the supposed virtues of Tar Water, made public in successive editions of his treatise by so illustrious an author, have not saved it from neglect and disgrace, it may be fairly assumed that they were mainly imaginary.

The bishop, as is usual in such cases, speaks of himself as indispensably obliged, by the duty he owes to mankind, to make his experience public.  Now this was by no means evident, nor does it follow in general, that because a man has formed a favorable opinion of a person or a thing he has not the proper means of thoroughly understanding, he shall be bound to print it, and thus give currency to his impressions, which may be erroneous, and therefore injurious.  He would have done much better to have laid his impressions before some experienced physicians and surgeons, such as Dr. Mead and Mr. Cheselden, to have asked them to try his experiment over again, and have been guided by their answers.  But the good bishop got excited; he pleased himself with the thought that he had discovered a great panacea; and having once tasted the bewitching cup of self-quackery, like many before and since his time, he was so infatuated with the draught that he would insist on pouring it down the throats of his neighbors and all mankind.