i6o THEORETICAL BIOLOGY 



Now there are a whole number of tools, the framework of 

 which does not express the entire counter-action ; and these 

 always require the help of other implements in order actually 

 to carry out a function. If, for instance, we take the nail 

 of a box, there is required for its counter-action (which backs 

 up our action of holding the box together) firstly, the hammer, 

 for the blows of which the head of the nail is suitably shaped, 

 and, secondly, the wood of which the box is made, the con- 

 sistency of which permits the nail to penetrate, but prevents 

 its coming out again easily. 



The framework of the nail, then, unlike that of the ladder, 

 is not in itself adequate for the exercise of a counter-action. 

 In addition, a hammer and some wood are necessary, if the 

 counter-action is to be achieved. If we give a special name 

 to the connection that exists, in strict conformity with plan, 

 between different implements not having any lasting material 

 association, we may speak of " inter-adjustment." In con- 

 trast to the framework, which word means a lasting functional 

 connection according to a rule, " inter-adjustment " means a 

 functional connection that appears only for a time ; it like- 

 wise is subject to a rule. 



Graber has called the effectors of animals their tools. 

 We might let this term pass, if the relations between tool 

 and material were not really far too general to do justice to 

 the extraordinarily close connection that is manifested in the 

 function-rule. 



In the function-circle, all the parts, even if not con- 

 crescent as in the organism, are nevertheless so perfectly 

 fashioned with relation to one another, that they form tem- 

 porarily an actual framework. Knowing this, we see that, in 

 considering the world of action, the biologist must follow a 

 completely different route from that taken by the physiologist. 

 To define briefly the very different attitudes of the two 

 sciences, we may say that physiology regards the effectors of 



