86 THE NATURE OF LIFE 



organism and compare its electrical con- 

 dition with a normal or an unstimulated 

 portion. 



It is well known that activity and in- 

 jury are commonly accompanied by an 

 increased production of carbon dioxide 

 and in view of this it is not surprising 

 that electrical changes should occur. In 

 any case we shall probably not go far 

 wrong in thinking that a study of the 

 chemical changes will give us the key to 

 the explanation of the electrical phenom- 

 ena. 



Certain other electrical manifestations 

 of living matter are apparently of univer- 

 sal occurrence as, for example, the fact 

 that if an organism be brought into con- 

 tact with a salt solution at one point and 

 with a more concentrated one at another 

 p)oint the latter is electrically negative 

 with reference to the other. This, how- 

 ever, can be easily imitated with non- 

 living materials. 



If an organism is connected to a gal- 

 vanometer by unpolarizable electrodes 



