ANIMAL AND VEGETABLE 141 



oxygen, a complex electro-chemical action between it and 

 the iron in the cell may be set up, which by attraction and 

 repulsion gives rise to the observed phenomena. 



In this connection reference may usefully be made to 

 the experiments of Ampere. He proved by means of 

 movable wires that attraction was shown when the currents 

 ran in the same direction and repulsion when in opposite 

 directions ; also that when two finite currents are inclined 

 to each other without crossing, they attract when both run 

 towards or both run away from the common apex, but 

 repel when one runs towards and the other away from the 

 apex. 



When the currents are in the same direction, the 

 surfaces oppositely electrified will be directly opposed, 

 and therefore attraction ensues. If the currents are in 

 opposite directions the surfaces similarly electrified will 

 oppose, and therefore repel each other. 



In protoplasm there are many possible " surfaces " in 

 the form of more or less vertical divisions of the cell. 



Supposing amoeboid movement to be due to either 

 attraction or repulsion, or both, causing the irregular 

 projections, we can understand that upon one current 

 momentarily ceasing to flow or diminishing in intensity 

 such projection would, wholly or partially, be withdrawn, 

 because it had its origin in the first instance in a force, and 

 upon that force being no longer operative or altering in 

 intensity a change of form would take place. 



It will be remembered that early in the last century 

 Davy passed a current through a solution of potash, and 

 finding that the potassium went to one of the poles and the 

 oxygen to the other, concluded that the two elements of a 

 compound are charged with different electricities, which 

 are neutralised on combination. That is the view now 

 held after so long, and so lamentable a loss of time. 

 " The actual theory of ionisation may be summed up 



