344 THEORETICAL BIOLOGY 



This simple idea, however, can be taken as a substitute 

 for the whole process, only if we bear in mind that here we 

 have to do, not with a mechanical but with a biological 

 framework. In every case, from the action of the one 

 collaborator a stimulus must proceed, which is converted 

 by the other into excitation, and this then leads to release 

 of the corresponding action. 



Accordingly the whole process must be described as a 

 transference of excitation from organism to organism, which 

 proceeds along fixed paths, because in each organism the 

 steering-apparatus is focussed on a certain excitation-indica- 

 tion, and after that appears, hands on the excitation to certain 

 effectors. 



The means whereby the excitation is transferred from 

 one human being to another in speech and writing become so 

 complicated, that we usually forget their significance as effector 

 pegs which fit into receptor sockets. 



The power to concentrate the steering-apparatus in the 

 individual man both on the receptor and on the effector 

 side with the degree of delicacy and accuracy required for 

 most sorts of work, is not present from the beginning, but 

 must be acquired through executing certain movements, and 

 through working out certain indications, which often appear 

 above the threshold only after others have been suppressed. 



And so it happens that the worker must be specially 

 trained for each vocation, before he can serve as a cog- 

 wheel in the community-machine. 



When we have succeeded in forming a picture of the com- 

 munity-machine, we shall be able to show that here, as in 

 every other machinery that has to run smoothly, the same 

 basic principles are in control ; namely, compulsion, variety 

 and subordination. 



We shall also learn to estimate the variety of form of the 

 worlds-as-sensed, which have to change with the vocation, 



