When we compare this celebrated work with the medical writings of the Greeks, and even of the Arabians, the predecessors of Avicenna, we shall be surprised that it contains little or nothing which can be considered as original; the whole is borrowed from the writings of Galen, or Ætius, or Rhazes: scarcely ever does he venture to trust his own wings, but rests entirely on the sagacity of his Greek and Arabian predecessors. Galen is his great guide; or, if he ever forsake him, it is to place himself under the direction of Aristotle.
The Canon contains a collection of most of the valuable information contained in the writings of the ancient Greek physicians, arranged, it must be allowed, with great clearness. The Hhawi of Razes is almost as complete; but it wants the lucidus ordo which distinguishes the Canon of Avicenna. I conceive that the high reputation which Avicenna acquired, was owing to the care which he bestowed upon his arrangement. He was undoubtedly a man of abilities, but not of inventive genius. There is little original matter in the Canon. But the physicians in the west, while Avicenna occupied the medical sceptre, had no opportunity of judging of the originality of their oracle, because they were unacquainted with the Greek language, and could not therefore consult the writings of Galen or Ætius, except through the corrupt medium of an Arabian version.
But it is not the medical reputation of Avicenna that induced me to mention his name here. Like all the Arabian physicians, he was also a chemist; and his chemical tracts having been translated into Latin, and published in Western Europe, we are enabled to judge of their merit, and to estimate the effect which they may have had upon the progress of chemistry. The first Latin translation of the chemical writings of Avicenna was published at Basil in 1572; they consist of two separate books; the first, under the name of “Porta Elementorum,” consists of a dialogue between a master and his pupil, respecting the mysteries of Alchymy. He gives an account of the four elements, fire, air, water, earth, and gives them their usual qualities of dry, moist, hot, and cold. He then treats of air, which, he says, is the food of fire, of water, of honey, of the mutual conversion of the elements into each other; of milk and cheese, of the mixture of fire and water, and that all things are composed of the four elements. There is nothing in this tract which has any pretension to novelty; he merely retails the opinions of the Greek philosophers.
The other treatise is much larger, and professes to teach the whole art of alchymy; it is divided into ten parts, entitled “Dictiones.” The first diction treats of the philosopher’s stone in general; the second diction treats of the method of converting light things into heavy, hard things into soft; of the mutation of the elements; and of some other particulars of a nature not very intelligible. The third diction treats of the formation of the elixir; and the same subject is continued in the fourth.
The fifth diction is one of the most important in the whole treatise; it is in general intelligible, which is more than can be said of those that precede it. This diction is divided into twenty-eight chapters: the first chapter treats of copper, which, he says, is of three kinds; permenian copper, natural copper, and Navarre copper. But of these three varieties he gives no account whatever; though he enlarges a good deal on the qualities of copper—not its properties, but its supposed medicinal action. It is hot and dry, he says, but in the calx of it there is humidity. His account of the composition of copper is the same with that of Geber.
The second chapter treats of lead, the third of tin, and in the remaining chapters he treats successively of brass, iron, gold, silver, marcasite, sulphuret of antimony, which is distinguished by the name of alcohol; of soda, which he says is the juice of a plant called sosa. And he gives an unintelligible process by which it is extracted from that plant, without mentioning a syllable about the combustion to which it is obvious that it must have been subjected.
In the twelfth chapter he treats of saltpetre, which, he says, is brought from Sicily, from India, from Egypt, and from Herminia. He describes several varieties of it, but mentions nothing about its characteristic property of deflagrating upon burning coals. He then treats successively of common salt, of sal-gem, of vitriol, of sulphur, of orpiment, and of sal ammoniac, which, he says, comes from Egypt, from India, and from Forperia. In the nineteenth and subsequent chapters he treats of aurum vivum, of hair, of urine, of eggs, of blood, of glass, of white linen, of horse-dung, and of vinegar.
The sixth diction, in thirty-three chapters, treats of the calcination of the metals, of sublimation, and of some other processes. I think it unnecessary to be more particular, because I cannot perceive any thing in it that had not been previously treated of by Geber.
The seventh diction treats of the preparation of blood and eggs, and the method of dividing them into their four elements. It treats also of the elixir of silver, and the elixir of gold; but it contains no chemical fact of any importance.
The eighth diction treats of the preparation of the ferment of silver, and of gold. The ninth diction treats of the whole magistery, and of the nuptials of the sun and moon; that is, of gold and silver. The tenth diction treats of weights.