THE CONQUEST OF DISEASE 



demonstrated by experiments upon animals 

 that the brain is the seat of the intellect. He 

 also discovered that the nerves have special 

 uses, some conveying feeling and others mo- 

 tion. But the dominant superstitions discred- 

 ited the work of this great man and soon the 

 physiology of the nervous system was sur- 

 rounded by mysticism. It was not until the 

 nineteenth century that Sir Charles Bell 

 (1810) completed the studies begun by Galen. 

 He experimented upon living animals and 

 developed exact knowledge concerning the 

 motor and sensory nerves. The difference in 

 function between the anterior and posterior 

 roots of the spinal nerves was thus discovered. 



The earliest experimenters differentiated 

 the functions of the cerebrum and the cerebel- 

 lum. They made gross tests which showed the 

 former to be the source of voluntary impulses, 

 and the latter the organ of coordination. 



Animal experiments were made by Flourens, 

 Luciani, and Horsley to determine the func- 

 tions of the cerebrum. After removing the 

 cerebrum from a frog or a pigeon all voluntary 

 motion ceases, but the animal possesses its 

 reflexes and vegetative functions. It sits 

 quietly in an apathetic state. It has the power 



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