ANIMAL AND VEGETABLE 59 



been hopelessly incompetent, and in their turn be subjected 

 to similar criticism at the hands of others. 



As a great deal which does not happen to be true has 

 been written about non-polarisable electrodes, it may be 

 well at this juncture to give an account of a few experiments 

 which were carried out with the object of exploding some 

 cherished theories. 



I found that when two wires of equal gauge and length, 

 soldered to two steel needles of exactly the same gauge 

 and length, were connected to the terminals of the gal- 

 vanometer, and the needles were inserted in various objects 

 and liquids, certain deflections were observed deflections 

 which were not momentary, but more or less constant. 



These deflections are explained as being due to galvanic 

 action. 



There are two theories, i.e. 



(1) Two metals that is to say, one electrode being 



electrically positive to the other in one solution, 

 or 



(2) One metal in two solutions. 



It will, however, be only necessary to consider the first 

 seriously, inasmuch as there cannot be two different fluids 

 in distilled water, while the most careful analysis has 

 failed to reveal the presence of two widely differing solu- 

 tions in the juices of fruits and vegetables. Nor can the 

 first hypothesis be sustained, if only for the reason that the 

 sign of the deflection obtained is not altered by the reversal 

 of the needles upon the terminals of the galvanometer. 



In the case of liquids such as distilled water, and all 

 lifeless moist objects, the deflections given by them must 

 be of the same sign, and that sign is, and must be, governed 

 by the sign of the electricity or neuro- electricity with which 

 the air of the testing-room is, for the time being, charged ; 

 that is to say, when the two wires and electrodes are of the 

 same metal and of equal resistance, the deflections which 



