PHILOSOPHER. SCIENTISTS 



and other such actions as are natural and usual in the 

 body, and which depend on the course of the spirits, 

 are like the movements of a clock, or a mill, which may 

 be kept up by the ordinary flow of water." 

 , In such passages as these Descartes anticipates the 

 ideas of physiology of the present time. He believed 

 that the functions are performed by the various organs 

 of the bodies of animals and men as a mechanism, 

 to which in man was added the soul. This soul he 

 located in the pineal gland, a degenerate and presum- 

 ably functionless little organ in the brain. For years 

 Descartes's idea of the function of this gland was held 

 by many physiologists, and it was only the introduc- 

 tion of modern high - power microscopy that reduced 

 this also to a mere mechanism, and showed that it is 

 apparently the remains of a Cyclopean eye once com- 

 mon to man's remote ancestors. 



Descartes was the originator of a theory of the 

 movements of the universe by a mechanical process 

 the Cartesian theory of vortices which for several 

 decades after its promulgation reigned supreme in 

 science. It is the ingenuity of this theory, not the 

 truth of its assertions, that still excites admiration, for 

 it has long since been supplanted. It was certainly 

 the best hitherto advanced the best "that the ob- 

 servations of the age admitted," according to D'Alem- 

 bert. 



According to this theory the infinite universe is full 

 of matter, there being no such thing as a vacuum. 

 Matter, as Descartes believed, is uniform in character 

 throughout the entire universe, and since motion can- 

 not take place in any part of a space completely filled, 



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