THE MACHINERY OF THE BRAIN 245 



the first cranial or olfactory nerve and also from the fifth 

 cranial nerve. If what he had been taught was true, 

 namely, that all nerves carried the same kind of sensations 

 or messages, and that such messages could pass along both 

 to and from the brain in the same nerve, then Nature 

 had done a superfluous thing in giving the lining mem- 

 brane of the nose a double nerve supply. One nerve 

 should have been sufficient. Hunter had already learned 

 that Nature was an economical as well as an expert con- 

 structor, and that she must have had a definite reason 

 for providing the nose with nerves from both first and 

 fifth cranial nerves. He rightly concluded that these two 

 nerves subserved different functions : the first or olfactory 

 being for the detection of smell, the other — the fifth — for 

 common sensation. He further inferred that the nerve 

 from the eyeball could carry only sight-messages, the 

 nerve from the ear only sound-messages, and nerves of 

 the tongue only taste-messages. The rest of the nerves 

 of the body he grouped together as a common kind, and 

 evidently believed, as the ancients did, that they could 

 carry messages in either direction. 



We have gone to John Hunter, not because he made 

 a great discovery about nerves, but simply because he 

 realised, what other men failed to see, that the manner 

 in which nerves are distributed to the body cannot be 

 explained unless it is supposed that they serve different 

 offices. 



We are now to watch another young Scotsman make 

 a discovery of the greatest importance concerning the 

 machinery of the nervous system. In 1804, eleven 

 years after John Hunter's death, Charles Bell arrived in 

 London from Edinburgh, where he had been trained as 

 an anatomist and surgeon. He was unlike Hunter in 

 many ways — very attentive to outward appearances and 

 somewhat of a dandy in the matter of clothes. He had 

 already passed his twenty-eighth year on his arrival in 

 London ; he was poor, ambitious, and highly educated ; 

 his sole hope of success lay in the publication of a manu- 

 script he carried in his travelling valise. It was a treatise 



