THE LIVING SUBSTANCE. 135 



Nothing, I think, shows more clearly that the stable sub- 

 stance as organism is merely a device for securing, and for 

 elaborating and storing the specific environment for the sub- 

 stance as such, and especially for the perpetuation areas of 

 this, than the facts connected with the history of these latter. 

 In the case of development of embryonic forms, we see the 

 organism for long periods wholly independent of external envi- 

 ronment as a source of supply, for it bears within itself all that 

 is most essential to its growth, and without which it could not 

 exist at all, no matter how favorable were all external conditions 

 outside the eggshell, or membrane, or jelly-like covering it has 

 been directly or indirectly provided with by the parent organism. 

 And often the parent's own body wall shields and isolates it 

 for long periods. 



[128] From the offered standpoint there vanishes that para- 

 doxical mystery which surrounds preparation for larval or adult 

 environmental conditions never experienced by an organism. 

 Such phenomena express a reaction to already existing environ- 

 ment. This is potent before opportunity to use an organ so 

 formed arises, simply because it is in a sense independent of 

 this. Such is the characteristic formation of cilia before the 

 membrane of the egg is broken through; or of a double pelli- 

 cular plate within the blastomere of an echinus Q.gg before 

 segmentation; akin also is the phenomenon of the beaver 

 building his winter dam with fire-irons on a parlour carpet. It 

 is all to be summed up in the saying that the substance's acts 

 are based on its own internal conditions, and that all those 

 structures which seem to precede function do not, after all, actually 

 do so, for they are, in the first place, substance orgaiis before they 

 are organism organs. 



Peculiarly is the selection of certain portions of external 

 environment by the organism for the substance as such, a 

 similar manifestation of the same habit as a selection of cer- 

 tain conditions by the substance as organism, either for itself, 

 or for those portions of itself destined as newly incorporated 

 organisms to outlive its older self. 



[129] The fact should be kept well in view that, before its 

 separation, an egg or bud has been simply an organized area 



