62 



THE NERVOUS SYSTEM 



The relation of Magendie's work on the nerve- 

 roots to Bell's work need not be considered here. 

 The exact dates of Bell's observations are given by 

 one of his pupils in the Preface to the 1830 volume. 

 Magendie finally proved the sensory nature of the 

 posterior nerve-roots : " The exact and full proof 

 which he brought forward of the truth which 

 Charles Bell had divined rather than demonstrated, 

 that the anterior and posterior roots of spinal 

 nerves have essentially different functions — a truth 

 which is the very foundation of the physiology of 

 the nervous system — is enough by itself to mark 

 him as a great physiologist." (Sir M. Foster, 

 loc. cit.) 



2. Marshall Hall (1790-1857). 



Reflex action had been studied long before the 

 time of Marshall Hall. The Hon. Robert Boyle 

 (1663) had observed the movements and actions of 

 decapitated vipers, flies, silkworms, and butterflies. 

 Similar observations were made on frogs, eels, and 

 other lower animals, by Redi, Woodward, Stuart, 

 Le Gallois, and Sir Gilbert Blane. According to 

 Richet, it was Willis who first gave the name reflex 

 to these movements. 



It cannot be said that these first studies of reflex 

 action did much for physiology. But the following 

 translation from Prochaska (1800) shows how they 

 cleared the way for Marshall Hall's work, by the 

 proof that they gave of the liberation of nervous 

 energy in the spinal cord : — 



" These movements of animals after decapita- 

 tion must needs be by consent and commerce 



