ANIMAL ELECTRICITV. LECTURE H. 31 



indeed its own language, instrumental as well as 

 verbal, and it only happens too often that students of 

 closely allied phenomena fail to exchange lights for no 

 other reason than that they do not understand each 

 other's jargon. 



The first steps in a language are generally the 

 dullest and most repulsive, but only by reason of 

 those steps taken does any language bear its message 

 to us. Where can be the interest of black marks on 

 paper if we cannot read them, or of a spot of light 

 wandering along a scale if we do not know what it is 

 saying. 



''Current," "Pressure," "Resistance," "Galvano- 

 meter," are some of the ABC labels that must have 

 some meaning for us before we may be permitted to 

 proceed a step further otherwise than as sham 

 students. 



Well, these labels having a meaning for us — I do 

 not say their full and complete meaning — ^I should 

 next ask you to make sure that we understand what is 

 meant by saying that "current varies with pressure 

 and inversely as resistance," and then being sure of 

 my ground, I should invite you to follow me in the 

 not very complicated details of the special case here 

 figured. 



The central object is the nerve, lying upon two 

 pairs of electrodes, inside a glass chamber, through 

 which gases and vapours can be driven. The nerve 

 must not dry, therefore gases are made to pass in 



