404 THE EVOLUTION THEOEY 



prove. There are thousands of kinds of ' constellations ' of elementary- 

 substances and forces which condition the activity of the living machine, 

 and only when all these constellations are present in the proper 

 manner and in the proper relations to each other can the functions 

 of the organism be properly discharged. 



But the living machine differs essentially from other machines in 

 the fact that it constructs itself ; it arises by development from a cell, 

 by going through numerous 'stages of development.' But none of 

 these stages is a dead thing, each is itself a living organism whose 

 chief function is to give rise to the next stage. Thus each stage of 

 the development may be compared to a machine whose function 

 consists in producing a similar but more complex machine. Each 

 stage is thus composed, just like the complete organism, of a number 

 of such 'constellations' of elementary substances and elementary forces, 

 whose number in the beginning is relatively small, but increases rapidly 

 with each new stage. 



But whence come these ' constellations ' or, to keep to our metaphor, 

 the levers, wheels, and cranks of each successive stage in the making 

 of the organic machine? The epigenetie theory of a germ-plasm 

 without primary constituents answers by pointing to internal and 

 external influences which cause the germ-plasm, originally homo- 

 geneous, to differentiate gradually more and more, bringing it into 

 the most diverse 'constellations.' But how can such influences 

 introduce new springs, levers, and wheels of a quite specific kind, as 

 must be the case if apparently similar germinal substances are to 

 give rise to two such different animals as a domestic duck and 

 a teal ? The cause must lie in the invisible differences in the proto- 

 plasm, opponents will answer, and we with them. But our studies up 

 to this point have shown us that the differences cannot be merely 

 elementary differences, cannot be merely of a physico-chemical nature 

 depending on the composition of the raw material and the implicated 

 energies ; they must depend on the definite co-ordination of substances 

 and energies, in other words, on the occurrence of ' constellations ' of 

 these./ Thus the germ-plasm must be composed of definite and very 

 diverse combinations of living units, which are themselves bound up in 

 a higher ' constellation,' so that they act as a living machine at the 

 first stage of development, and liberate into activity the already 

 existing constellations of the second stage. The second stage in the 

 series of living machines which arise successively from each other 

 liberates the sleeping ' constellations ' for the third, and so on. 



These ' constellations ' of matter and energy are the biophors, the 

 determinants, and the ' groups of determinants ' which we may think 



