There arose, naturally, strenuous opposition to the views and teachings of Boerhaave, and his principal opponent was Stahl (1660-1734), who was one of the most important systematists of any age, a profound thinker, and a pioneer chemist. He began lecturing in Jena at once upon his graduation, at the age of twenty-five, and moved through two or three different university positions until he came to Berlin at the age of fifty-six. He was a great pietist, of uncouth manners, faithful to his laboriously acquired convictions, and bitter and relentless against those who could not accept them. Indeed, he regarded his convictions as revelations from God. He looked upon the success of another as a personal injury to himself, and from being first a croaker he became finally a confirmed misanthrope, until he fell into actual melancholia. Pecuniary profit he had never sought, and its pursuit he scorned.{196} His views were dynamico-organic, pietistic, and antagonistic. He regarded the soul as the supreme principle, life-giving and life-preserving, not to be confounded with the spirit; when hindered or obstructed in its operation, disease was present. The soul governed the organism chiefly by way of the circulation; consequently, plethora played an important rôle. To get rid of this plethora the soul employed either fever or convulsive movements; for example, in children plethora produces a pressure of blood to the head, and, by way of compensation, the soul provides a haemorrhage from the nose. For reasons easily appreciated, he regarded bleeding piles as safety-valves of the utmost importance. Fever was a salutary effort of the soul to preserve the body; this was true even of intermittents, and, accordingly, he never gave cinchona. He scorned anatomy and physiology, saying, in one place, that medicine had profited as much by the knowledge of the bones in the ear as by a knowledge of snow which had fallen ten years previously. But Stahl was one of the most eminent chemists of the age, and did a great deal to liberate chemistry from the glamour of alchemy and the domination of pharmacy, and to transform it into an independent science. Stahl's doctrine has been called _animism_, and was a reaction against the chemical and mechanical theories of the seventeenth century. He gained a considerable number of followers, the most notable of them among the French being Sauvages (1706-1767), the forerunner of Pinel and an opponent of pure mechanics, who animated the mechanical system of the body with Stahl's "soul." This was, par excellence, the age of artificial systems, and so Sauvages in his classification supplied a system which had ten classes of diseases, each of which had several orders, and some as many as two hundred and ninety-five genera, and two thousand four hundred species of disease!! Even Linnæus had three hundred and twenty-five genera of disease,{197} while Cullen had only four classes with one hundred and forty-nine genera.