A HISTORY OF SCIENCE 



ably not his own invention, but borrowed from his 

 friend Galileo. 



Harvey's discovery of the circulation of the blood 

 laid the foundation of the I air o physical school by 

 showing that this vital process was comparable to a 

 hydraulic system. In his On the Motive of Animals, 

 Borelli first attempted to account for the phenomena 

 of life and diseases on these principles. The iatro- 

 mechanics held that the great cause of disease is due 

 to different states of elasticity of the solids of the body 

 interfering with the movements of the fluids, which 

 are themselves subject to changes in density, one or 

 both of these conditions continuing to cause stagna- 

 tion or congestion. The school thus founded by 

 Borelli was the outcome of the unbounded enthusiasm, 

 with its accompanying exaggeration of certain phe- 

 nomena with the corresponding belittling of others 

 that naturally follows such a revolutionary discovery 

 as that of Harvey. Having such a founder as the 

 brilliant Italian Borelli, it was given a sufficient im- 

 petus by his writings to carry it some distance before 

 it finally collapsed. Some of the exaggerated mathe- 

 matical calculations of Borelli himself are worth not- 

 ing. Each heart-beat, as he calculated it, overcomes 

 a resistance equal to one hundred and eighty thousand 

 pounds; the modern physiologist estimates its force 

 at from five to nine ounces! 



THOMAS SYDENHAM 



But while the Continent was struggling with these 

 illusive " systems," and dabbling in mystic theories 

 that were to scarcely outlive the men who conceived 



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