302 PROGRESS OF SCIENCE IN THE CENTURY. 



well known that nerves stimulated and controlled 

 muscular activity, that the nervous system was the 

 seat of feeling and thought, that different parts of 

 the brain had different functions, and so on, but the 

 mechanism of nerve ganglia and nerve fibres was 

 almost unknown, though some physiologists were 

 pondering over it. Indeed the history of the subject 

 may be said to begin with 1811, when an English 

 surgeon, Charles Bell, privately published a pam- 

 phlet setting forth a " ISTew Idea," that " the nerves 

 are not single nerves possessing various powers, but 

 bundles of different nerves, whose filaments are united 

 for the convenience of distribution, but which are 

 distinct in office as they are in origin from the brain." 

 As Sir Michael Foster has said, " our present knowl- 

 edge of the nervous system is to a large extent only 

 an exemplification and expansion of Charles Bell's 

 ' New Idea,' and has its origin in that." * 



" During the latter part of the present century, and 

 especially during its last quarter, the analysis of the 

 mysterious processes in the nervous system, which issue 

 as feeling, thought, and power to move, has been pushed 

 forward with a success conspicuous in its practical, and 

 full of promise in its theoretical, gains. That analysis 

 may be briefly described as a following up of threads. 

 We now know that what takes place along a tiny thread 

 which we call a nerve-fibre differs from that which 

 takes place along its fellow-threads, that differing 

 nervous impulses travel along different nerve-fibres, and 

 that nervous and physical events are the outcome of 

 the clashing of nervous impulses as they sweep along 

 the closely-woven web of living threads of which the 

 brain is made. We have learnt by experiment and by 

 observation that the pattern of the wel3 determines the 

 play of the impulses, and we can already explain many 

 * Pres. Address. Rep. Brit. Ass. for 1899, p. 11. 



