EXPERIMENTAL MORPHOGENESIS 139 



physical and of chemical constituents, by the acting of which 

 a typical effect is attained. We, in fact, lay much stress 

 upon embracing in our definition of a machine the existence 

 of chemical constituents also ; we therefore understand by 

 the word " machine " a configuration of a much higher degree 

 of complication than for instance a steam-engine is. Of 

 course a machine, whose acting is to be typical with regard 

 to the three dimensions in space, has to be typically con- 

 structed with regard to these three dimensions itself ; a 

 machine that was an arrangement of elements in a strict 

 plane could never have typical effects at right angles 

 to that plane. This is a point which must well be kept 

 in mind in all hypothetical considerations about machines 

 that claim to explain morphogenesis. 



It must be granted that a machine, as we understand 

 the word, might very well be the motive force of organo- 

 genesis in general, if only normal, that is to say, if only 

 undisturbed development existed, and if a taking away of 

 parts of our systems led to fragmental development. 



But we know that, at least in our harmonious- 

 equipotential systems, quite another process occurs after parts 

 have been taken away : the development that occurs is not 

 fragmental but whole, only on a smaller scale. 



And we know, further, that this truly whole develop- 

 ment sets in irrespective of the amount and direction of the 

 separation. Let us first consider the second of these points. 

 There may be a whole development out of each portion of 

 the system above certain limits which is, say, of the 

 volume V. Good ! Then there ought to exist a machine, like 

 that which exists in the whole undisturbed system, in this 

 portion V also, only of smaller dimensions ; but it also 



