156 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



systems are merely formal, and indeed I am prepared to 

 concede that we shall not learn anything altogether new 

 from their discussion : their analysis would lead either to 

 what was our " first proof ' of the autonomy of life- 

 phenomena or to what will be our " second " one. But the 

 mere descriptions of the facts discovered here will interest 

 you, I think, and will fill your minds with more vivid 

 pictures of the various aspects of form-autonomy. 



While dealing with our harmonious-equipotential systems 

 as the starting-points of processes of restitution, e.g. in 

 Tubular ia, Clavellina, the flat worms, and other instances, 

 we always have regarded cross-sections of the body as 

 constituting the elements of equipotentiality. Now cross- 

 sections, of course, are by no means simple in themselves, 

 but are made up of very different tissues, which are 

 derivates of all three of the original germ layers 

 ectoderm, rnesoderin, and endoderm. Owing to this com- 

 posite character of the cross-sections, taken as elements of 

 harmonious systems, a special phenomenon of morpho- 

 genesis is presented to us, which teaches somewhat more 

 than the mere concept of harrnonious-equipotentiality can 

 express. If composite elements concerned in morpho- 

 genesis result in one whole organisation in spite of the 

 development of the single tissues of these elements going 

 on independently, then there must be a sort of corre- 

 spondence or reciprocity of the harmonious development 

 among these tissue constituents themselves ; otherwise a 

 proportionate form could not be the final result. We may 

 conveniently speak of a reciprocity of harmony as existing 

 between the single tissues or germ layers which constitute 

 many harmonious-equipotential systems, and there can be 



