The Chemical, or Iatrochemical, System was originated by le Bôe, commonly known as Sylvius (but who must not be confounded with the great anatomist of the same name). Le Bôe was born in Hanau in 161-4; studied in Paris, Leyden, and Basel; received his doctorate from the latter university at the age of twenty, and practiced in Switzerland with great success until 1660, when he accepted{170} a professorship in Leyden; here he was distinguished for his eloquence, wealth, and sociability, as well as for the great number of pupils that were attracted by his clinical method of teaching. His system embraced a peculiar phantasy, being based upon the elements of chemistry, the new knowledge of the circulation, the latest physiological teachings, and the old doctrine of the spirituous or innate heat of the heart, which he claimed to have felt with his finger. He asserted his theories were founded upon experience, but the truth is, they were inaccurate deductions from experimental observations, many of which were wholly irrelevant. The majority of diseases, he taught, were produced by excess of acidity or alkalinity. For him, the three great fluids of the body were the saliva, the pancreatic fluid, and the bile, while health consisted in the undisturbed performance in the body of the process of fermentation; and the saliva was supposed to give rise to hectic fevers, because such manifest exacerbation after eating. Stereotyped theory and equally stereotyped therapeutics gained for him, for a short time, a large following, but later raised numerous opponents, who alleged that his system caused as many human lives as the whole thirty years' war. He died in 1672. To the same iatrochemical school is generally assigned Thomas Willis, born in Oxford in 1622 (died in 1675), who rendered great service to anatomy, especially to anatomy of the nervous system, although his teaching was disfigured by certain unsupported theories. Like Van Helmont, he had been destined for theology, but turned his attention to medicine. Ultimately he became Professor of Philosophy in the University of Oxford. He first described the so-called circle of Willis, whence its name; also ascribed diseases, especially those of the blood, to fermentation, in which the vital spirits played the chief part. He accounted for hysteria, for instance, by the union of the spiritus with imperfectly purified blood. CHAPTER VII.