EXPERIMENTAL PSYCHOLOGY 



vertebrates in 1825. Desmoulins made at least one 

 discovery of epochal importance. He observed that 

 the brains of persons dying in old age were lighter than 

 the average and gave visible evidence of atrophy, and 

 he reasoned that such decay is a normal accompani- 

 ment of senility. No one nowadays would question 

 the accuracy of this observation, but the scientific 

 world was not quite ready for it in 1825; for when 

 Desmoulins announced his discovery to the French 

 Academy, that august and somewhat patriarchal body 

 was moved to quite unscientific wrath, and forbade 

 the young iconoclast the privilege of further hearings. 

 From which it is evident that the partially liberated 

 spirit of the new psychology had by no means freed 

 itself altogether, at the close of the first quarter of the 

 nineteenth century, from the metaphysical cobwebs of 

 its long incarceration. 



FUNCTIONS OF THE NERVES 



While studies of the brain were thus being inaugu- 

 rated, the nervous system, which is the channel of 

 communication between the brain and the outside 

 world, was being interrogated with even more tangible 

 results. The inaugural discovery was made in 1811 

 by Dr. (afterwards Sir Charles) Bell, 1 the famous Eng- 

 lish surgeon and experimental physiologist. It con- 

 sisted of the observation that the anterior roots of the 

 spinal nerves are given over to the function of convey- 

 ing motor impulses from the brain outward, whereas 

 the posterior roots convey solely sensory impulses to 

 the brain from without. Hitherto it had been supposed 

 that all nerves have a similar function, and the peculiar 



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