Whatever may be the destinies of nations in the wreck of empires and the destruction of men, the philosopher calmly seated on ruins that often "speak that sometime they were a worthy building," reflects with pride that science has withstood the withering hand of time. It is true, that in every study errors have been heaped upon errors; but truth will often result from falsehood, and doubt that brings on investigation, leads to comparative certainty. Locke has justly observed, that the faculty of reasoning seldom or never deceives those who trust to it: its consequences, from what it builds on, are evident and certain; but that which it oftenest, if not only, misleads us in, is, that the principles from which we conclude, the grounds upon which we bottom our reasoning, are but a part--_something_ is left out which should go into the reckoning to make it just and exact. This _something_ is the constant pursuit of the philosopher. The name of a country may be obliterated from a map, the deeds of heroes be effaced from the annals of the world; the pursuit of truth can only cease when man is no more;--its light may be veiled by ignorance, craft, or cupidity,--but it cannot be extinguished. The cities that gave birth to the illustrious philosophers of old have long ceased to exist, yet the immortal works of those sages that have escaped the ravages of time, are still as fresh and luxuriant as when their glorious oratory enchanted and captivated their disciples' ears. No science has been cultivated with more difficulty than that of Medicine. The following papers will show how fearfully it has had to contend in turn with the power of priestcraft, that sought to monopolize its practice, as a privilege from the gods, and with the furious opposition of contemporary members of the profession, whose cupidity and vanity were alarmed by the introduction of novel doctrines, which they were too old, too busy, or too obstinate to learn. The extracts from Medical Literature that I have given will show that most of our modern notions were known to the earliest writers, and were only improved in succeeding ages, as in like manner our present doctrines will in all probability be advanced by future generations. The destruction of kingdoms and of chronicles, the inroads of barbarism,--the more destructive inroads of ignorance and bigotry, have not been able to produce a void in the world of science; the catenation of philosophic inquiry has never been broken in its connexions. Oppression only riveted the chain more firmly, as if to resist the united power of man and time. Adversity, which Like the toad, ugly and venomous, Wears yet a precious jewel in its head, has always been considered the best school of practical wisdom: and it is thus that, amidst the portentous events which have shaken every institution, and which perhaps still menace further dissolution, the fane of science has oftentimes been more vividly illumined by the surrounding conflagration.