260 PHYSIOLOGY OF xMUSCLES AND NERVES. 



regardid as composed of many particles arranged one 

 behind tlie other, each of which is retained in a defi- 

 nite position by its own forces and by the influence 

 of the neighbouring particles. Whatever acts as an 

 irritant on the nerves must displace these particles 

 from this position, and must cause a disturbance, which 

 then propagates itself, owing to the fact that a change 

 in the position of one particle causes a disturbance in 

 the equilibrium of the adjacent particle s, in consequence 

 of which the latter are set in motion. Negative varia- 

 tion must be regarded as a result of this movement of 

 the nerve-particles, in that the electrically acting parts 

 are arranged in different order by the movement, and 

 therefore must exercise a different external influence. 

 But just as this change in the position of the nerve- 

 particles is able to set the needle of a multiplier, if it 

 is properly connected with the nerve, in motion, so the 

 electric process originating in the nerve must act on 

 the muscle, if the latter is sensitive to electric varia- 

 tions. This was the assumption from which we started, 

 and which, after the above explanations, will be regarded 

 as thoroughly trustworthy. To enter further into the 

 details of the activity of nerves and muscles, and to 

 substitute more definite conceptions for such as are at 

 present often indefinite, is impossible in the present 

 state of knowledge. 



