INHIBITION AND CARDIAC VAGUS 103 



But assuredly Wrightson's Theory of Hearing, which has 

 able advocates, throws doubt on many accepted opinions. 

 Moreover, those who have had the doubtful advantage of 

 receiving a severe and unexpected electric shock with a 

 powerful muscular reaction which, as it seems, might in 

 some cases tear away a ligament or even snap a bone, will 

 have suspicions of the " trigger " doctrine. If the function 

 of the vagus is not to produce some kind of excitation, the 

 phrase " trigger action " does not apply. " Trigger action " 

 in a gun is a measurable amount of energy, and so is the 

 energy in the cartridge. And in ordinary cases, where 

 the gun and the cartridge are what we may call " physio- 

 logical," that is, in such a state that the normal hammer 

 fall produces the normal explosion, an abnormally powerful 

 hammer impact will produce no more powder energy than a 

 merely adequate one. Yet if a powerful nerve excitation 

 occurs, there is more than a normal explosion of muscle 

 energy. In this case, if the nerve acts as a whole, more 

 energy does " go over," for, if in ordinary conditions 

 only a few fibres are affected, with the stronger stimulation 

 all may be called into play. In either case the facts suggest 

 that more energetic stimulation does cause greater, or even 

 disastrous effects, showing that " trigger action " is not a 

 sound analogy. It is therefore easy to understand how it 

 is that abnormal vagal stimulation results in " shock ' 

 or disintegrating action. There seem more analogies 

 between electric and nervous phenomena than the usual 

 nerve theories allow. For if in electric " flex," composed 

 of a large number of very fine wires, some of these fibres 

 are cut, the lamp does not light, whereas, if more volts arc 

 applied to the unaltered wire, " shock " results, and the 

 incandescent filaments fuse. It should be remembered 

 that action resulting in shock is not an entity, totus, teres 



