VOL. III.] PHILOSOPHICAL TRANSACTIONS. 289 



There is a third part of the same author's letters yet remaining untranslated, 

 which is likely to follow very shortly, with some other tracts concerning Man, 

 and the Union of the Rational Soul with the Body ; whereof the former was 

 written by Descartes himself, the latter by the ingenious D. de la Forge upon 

 Cartesian principles. 



III. Scrutinium Chymicum Vitrioli, Auth. Joh. Georgio Trumphio, Jenae, 

 1667. 



This author endeavours in this small tract to show the nature, difference, 

 choice, qualities and medical virtues of vitriol, together with the various ways of 

 preparing both dry and liquid medicines out of that mineral. He describes the 

 method of preparing vitriol used at Goslar in Germany, his native country. 

 This process is now so generally known, that it cannot be necessary to insert 

 the account of it here. 



IV. Francisci de le Boe Sylvii* Praxeos Medicae Idea nova, Lugd. Batav. 

 12mo. 1667. 



In this treatise the author endeavours to assign the nature, causes, symp- 

 toms, and remedies of every disease. He introduces many speculations con- 

 cerning fermentation ; the noxiousness of all such things as either destroy or 

 dull the acid spirit of the body in the work of nutrition ; the dominion of 

 the three humours in the body of animals, viz. the gall, the pancreatic juice, 

 and the saliva, and their mixture, either immediate or mediate, with the blood 

 returning to the heart ; as also their great influence when they are vitiated in 



* F. de le Boe Sylvius was descended from an ancient and noble family, and born at Hanau in 

 1614. After studying at Le)'den, he went to Paris, and from thence to Basil in Switzerland, where 

 he took his doctor's degree. He practised first at Hanau, tlien at Leyden, and afterwards at Amster- 

 dam, until the year l658 ; when he was appointed to the professorship of physic in tlie university of 

 Leyden. Here he continued teaching with almost unprecedented celebrity until tlie time of his 

 death, which happened in l672, when he was in the 58th year of his age. Sylvius was an expert 

 anatomist, and bestowed great attention on the dissecting and examining of bodies dead of different 

 diseases. These dissections he regarded as so important towards an accurate knowledge of the seats, 

 progress, and termination of diseases, that he caused a dissecting room for tlie examination of such 

 patients as die of remarkable disorders, to be annexed to the hospital. He was one of the earliest 

 defenders of Harvey's discovery of the circulation of the blood. He was moreover well versed in the 

 chemistry of his days j but it was by his medical theories, at that time almost universally adopted, 

 tliat he acquired so great a degree of fame. They produced among physicians a revolution of opinion^ 

 and made him the founder of a new medical sect. He taught that certain acidities and fermentations, 

 and particularly the effervescence of the pancreatic juice with the bile, were the chief causes of dis- 

 eases, and that the proper remedies for counteracting these diseases were absorbents, alkaline salts, 

 both fixed and volatile, and opium. These theories, so little reconcileable to the condition of the 

 living body either in health or disease, are now justly exploded. Besides the work here mentioned, 

 Sylvius wrote various physiological and medical tracts, which after his death were printed collectively, 

 under the title of Opera Medica, 4to, Amsterdam l679j and Genev. folio, l680. 



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