18 BOERHAAVE 



than the power of 1,350 pounds." This estimate of the power of the 

 ' human muscles of mastication, is rather high. Canon in his recent 

 work places the pressure which the molars are capable of exerting at 

 270 pounds. Borelli admits, however, that certain animals ''consume 

 V flesh and bone by means of a certain very potent ferment, much in 

 ^ the same way as corrosive liquids dissolve metals." The iatro-phys- 

 ^ ical school eventually went farther than Borelli and denied that chem- 

 !; ical action has anything whatsoever to do with digestion, and con- 

 tended that digestion was mere trituration of the food in the stomach 

 to a creamy substance known as chyle. Bellini, a pupil of Borelli, 

 went farther in the beginning of the eighteenth century and endeav- 

 ored to explain many functions of the human body from mathemati- 

 cal data. Keill, a member of this cult, calculated from data purely 

 imaginary the power of each organ. According to him the stomach 

 had a force of compression so great that to overcome its own resist- 

 ance must have meant its own destruction. One iatro-physicist esti- 

 mated the force of the heart as equal to 180,000 pounds; another 

 placed it at eight ounces. Their calculations were clothed in the im- 

 posing nomenclature of the exact sciences. This doctrine is said to 

 have extended to all the universities and medical institutions of 

 Europe. 



The iatro-chemical school, or "chemikers" as they were dubbed 

 by Guy Patin, a French physician and wit of the time, sought a solu- 

 tion of all the phenomena of the human body in their flasks and re- 

 torts. They maintained that the change in the stomach was chiefly 

 if not wholly a chemical, resulting from the process of fermentation. 

 It was recognized even at this time that the membrane of the stomach 

 was glandular in structure, and yet little importance was attached to 

 the secretion of such membraneous surface. 



In 1614 was born Francois de le Boe or Dubois, better known by 

 his Latin name, Sylvius. He is not to be confused with Jacobus Syl- 

 vius, the Parisian anatomist, teacher of Vesalius, who lived in the 

 sixteenth century. The latter Sylvius studied at Sedan and at Basel, 

 where in 1637 he took his degree. He became professor of medicine 

 at Leyden, where he exerted a powerful influence until his death in 

 % 1672. Sylvius, though distinguished as a physician and physiologist, 

 ^ was essentially a chemist. Through his efforts the curators of the 

 Universtiy of Leyden built for him a ''Laboratorium" which, so far 

 • as we know, was the first university chemical laboratory. He devoted 

 a large part of his time to a study of salts, which he learned to rec- 

 ognize as resulting from the union of acids with bases. Sylvius looked 

 upon the phenomena of life from a chemical point of view. He was 

 well versed in that part of physiology derived by deductions from an- 

 atomy and by experiments on animals. His opinions on the circula- 

 tion and respiration were orthodox from our modem viewpoint. Har- 

 vey's teachings entered largely into his thoughts and it was chiefly 

 through his advocacy that the doctrine of the great discoverer of the 

 circulation of the blood became established in Holland. The contribu- 

 tions which Sylvius made to science were essentially chemical. 



Boerhaave — Herman Boerhaave, aready mentioned as a contrib- 

 utor to the chemical knowledge of alimentation, was born in 1668, 

 near Leyden, where he was educated. His early years were largely 



devoted to the classical and oriental studies. He became Ph. D. in 1690, 

 m. 



