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326 THEORETICAL BIOLOGY 



tion of the external stimuli. They determine directly what 

 shall serve as stimulus or indication, and what shall not, 

 since they form the internal framework anew, or repair it, 

 or rearrange it. 



Seen from this point of view, the difference between 

 machine and organism can be defined quite precisely. 



Both machines and organisms show two kinds of actions 

 which are essentially different from one another, (i) the action 

 of genesis, and (2) the action of function. But the action of 

 genesis in the organism (to which regeneration of destroyed 

 tissue is to be reckoned) is direct, whereas that of machines is, 

 without exception and in its very nature, indirect, since it 

 proceeds from the actions of its constructors, which are 

 conditioned by indications. The function-action of the 

 organism is always indirect, because it is built up on indica- 

 tions, whether these be fixed once and for all by the framework 

 that makes the selection, or, as in plastic actions, are con- 

 ditioned by the newly formed construction of the machinery. 



The function-action of the machine is, as a rule, direct, 

 and requires no releasing stimulus, because the whole system 

 is focussed on the effect of one definite external force, whether 

 that be the force of falling water, or whether it be heat, 

 as in the case of steam-engines. 



The super-mechanical actions of the organism resemble 

 inorganic actions in proceeding directly. Like the forces of 

 inorganic Nature, they are therefore the outcome of actual 

 natural factors. But they appear to contain a plan, because 

 they create a system, and so, on their side, they must be 

 referred back to a plan system. The Greeks also referred the 

 actions of inorganic Nature to a system, and we cannot 

 maintain that they were wrong in so doing. Even at the 

 present day we involuntarily base the concept of Nature on 

 the idea of a system. 



But the system that is expressed in the super-mechanical 



