184 THE POPULAR SCIENCE MONTHLY. 



function " of the spinal cord (which up to this time had been generally 

 looked on as a bundle of nerves), that the truth of Bell's doctrine came 

 at last to be fully established. For the movements called forth, by 

 irritation of the posterior roots were found to be due, not to the direct 

 transmission of motor impulses from them to the muscles, but to the 

 transmission of a motor nerve-current through the anterior roots, in 

 resj>onse to the stimulation given to the spinal cord itself by the 

 irritation of the posterior ; while, on the other hand, it was made 

 clear that the indications of pain given when the anterior roots are 

 irritated, are due to the presence, in those roots, of sensory filaments 

 derived from the posterior, which pass inward at the point of junction 

 between the two. But for the well-devised and carefully executed 

 experiments by which these difficulties were cleared up, the w^hole 

 matter would have remained in the state of uncertainty in which I 

 well remember it to have been, when I first entered on the study of 

 the subject, previously to Miiller's experiments. 



Having myself been afterward Sir Charles Bell's pupil (in surgery) 

 both in London and Edinburgh, I can testify from personal knowledge 

 that he himself never admitted that his discoveries needed any con- 

 firmation whatever ; but was always strong in the conviction, not only 

 that he had himself given all needful evidence of them, but that noth- 

 ing more remained to be done in the physiology of the nervous sys- 

 tem. It is not a little significant of his attitude of mind on this 

 subject, that he used to declare his complete inability to understand 

 "what Marshall Hall was driving at"; the doctrine of reflex action 

 independently of sensation being altogether "beyond his comprehen- 

 sion." As this last doctrine, which forms the basis of modern neurol- 

 ogy, is one which anatomy could scarcely even suggest, and which 

 nothing but experiment can demonstrate, I hope that Sir C. Bell's 

 opinion of the all-sufficiency of the study of anatomy for the advance- 

 ment of physiological science may henceforth be appreciated at its 

 true worthlessness. For I have shown, first, that Sir Charles Bell, 

 trusting to anatomy for his guidance, icent altogether wrong in the 

 first instance ; secondly, that it was by experiment on the nerves of 

 the face that he was led into the right track ; thirdly, that in regard 

 to these, through placing too much trust in his anatomical preconcep- 

 tions, and insufficiently testing them by further experiments, he was 

 led into mistakes which were only corrected by the experiments of 

 Magendie ; and, fourthly, that the most important discovery with 

 which he is usually credited that of the motor and sensory functions 

 of the anterior and posterior roots of the spinal nerves respectively 

 was only established in the true scientific sense by the experiments of 

 others working on his lines. Those experiments might have issued, 

 for any real proof ever given by Bell to the contrary, in establish- 

 ing some other doctrine of the spinal nerve-roots than that to which 

 he had been led by his study of the nerves of the face such, for 



