in ORGANIC ADAPTABILITY 35 



6. An organism then, as we are led to conceive it, may 

 be roughly described as a whole consisting of parts each of 

 which is conditioned in its behaviour, and even often in its 

 existence, by its relation to the remainder. These relations 

 are such that as the parts interact with one another and 

 with the outside world they tend to undergo a regular 

 series of changes which constitute the development of the 

 organism from birth to death. The general course of the 

 development is to this extent fixed by the original consti- 

 tution of the organism. But as the surroundings with 

 which it is brought into contact are infinitely various, what 

 may be called the typical course of development is a purely 

 imaginary line from which the life-history of any organism 

 diverges at every moment in greater or less degree. But 

 the forces that keep its various parts together are such 

 that within tolerably wide limits it can accommodate itself 

 to changes in the forces acting on it, maintaining its 

 existence, and even its general character, unchanged in their 

 despite. This is achieved by an appropriate modification 

 of its action, a change at one point for example compen- 

 sating a change at another, whereby under novel circum- 

 stances, or perhaps with grave modification of some part of 

 the organism itself, the plan of the whole is as nearly 

 constant as may be. If we sum all this up by saying that 

 the living organism is distinguished by its tendency to 

 maintain itself through process and against change we are 

 merely formulating the known facts. Underlying this 

 formula is the question whether this tendency is a true 

 conation or the result of an intricate combination of 

 mechanical parts so dovetailed that any disturbance of the 

 >rganic equilibrium at any point automatically sets up 

 :ompensating processes which tend to restore the balance, 

 strongest argument against this view is provided by 

 experimental mutilations. We can with difficulty conceive 

 machine so intricately planned as always, in all the varying 

 jsaults to which the living being is exposed, to yield that 

 reaction which tends to restore its normal method of work- 

 ing, as long as all its parts remain intact. But the very 

 lelicacy of such a machine would lead us to suppose that 

 breakage at any point must at least be fatal to the opera - 



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