12 THE ACTIVE FORCES OF LIVING ORGANISMS 



from the other substance brought within range. If 

 this be true, not only does the dual fluid theory dis- 

 appear, but we obtain in addition a clue to the 

 mysterious processes of natural reproduction ; for if 

 Tbe ether ^jjg ether is able to transmit influences from such a 



as a trans- 

 mitting substance as a piece of excited sealing-wax to a pith- 

 medium m *■ . 

 vegetal ball, and, so to speak, to impress to some extent its 



reprodue- .„ . . , 



tion. character upon it, we are justified in supposing the 



same medium might carry an influence or impulses 

 from the excited root or the excited leaf of a plant to 

 the equally excited seed. Further, the potential or 

 latent force stored in the latter supplemented from 

 without gives to the seedling its special form and 

 character. If in connection with the subject of heredity 

 transmission there be one truth deserving attention 

 more than another, it is that force is always the mould- 

 ing agent of matter, or, in other words, that the form 

 of matter can only be modified by matter in motion. 

 Properties In speaking of anything of so impalpable a nature 

 ether. as the ether, there is always some risk of attributing 

 to it, for the purposes of any argument, characteristics 

 which it does not really possess. At the same time, 

 however, our knowledge of it may perhaps be in- 

 creased by considering it in its relation to certain 

 natural phenomena, and by carefully examining and 

 comparing the consequences of our general concep- 

 tions of it. Thus, it is frequently said that the ether 

 constitutes an all - pervading, indivisible medium. 

 This latter property has been recently cited as a proof 

 that the ether is not the medium by which waves of 



