THE LIVING SUBSTANCE. 



157 



same powers required to see the flux of Protozoan forms, the 

 flux of substance in Metazoan forms can also, with greater 

 patience, be observed. Within and through the most complex 

 mechanism of cells, the continuous substance or formative 

 agent moves restlessly to and fro expressing itself as living 

 foam in countless different ways. Primarily protoplastic, it 

 builds up in relative localities of living masses specific deposits 

 of non-living material and maintains these in a general way, 

 without for the most part hampering its total liberty, merely 

 using them to make itself more free in and for self-expression. 

 In developmental phenomena, one sees the machinery of the 

 embryo formed by successive progressive shufflings of inclu- 

 sions already placed in it, and by more and more searching 

 rearrangements of these in relation to delicate pellicular mem- 

 branes of its living continuous substance. As differentiation 

 advances, area after area becomes markedly possessed, though 

 more or less unstably, of its own specific inclusions and certain 

 substances become wholly restricted for variable times to cer- 

 tain cell areas or to minuter areas within these. Nuclear 

 division phenomena seem to me to stand for subdivision of 

 specific conditioning material, for repetition of a local control 

 machinery having to do with general needs of the substance. 

 Whether as a ganglion or as nutritive control it is not possible 

 as yet to say certainly. Probably as both. 



The life history of perpetuation areas, their dependent rela- 

 tion to the foster machine or organism ; their relative im- 

 portance in time of famine as compared with other areas all 

 clamorous for food ; their long periods of reaction to the 

 internal environment provided for them ; their relative vigour 

 and vital power as compared with the parent organism when 

 first completed for self-support, or before this even ; — all 

 these things seem to me to declare that in these areas the 

 living substance is kept young or re-invigourated by sparing it 

 for a time all wasting activities and by feeding and cherishing 

 it in all ways, even if to do this be to sacrifice the parent 

 machine. The business of the substance is, after all, self con- 

 tinuation, rather than continuation or reproduction of an existing 

 grosser organism, which is but iticidental to its prime habits. 



