CHAPTER IX 



THE PRINCIPLE OF LEAST ACTION IN THE EVOLUTION 

 OF ORGANIC STRUCTURES 



In drawing attention to Directivity, so conspicuous 

 throughout the whole of the organic world, there is a 

 feature very observable in the structure of organs of all 

 kinds, which adds an additional value to the importance 

 of Directivity as one of the many coincident lines of 

 indubitable evidence which leads to the conclusion that 

 the Power behind Nature is not only conscious but 

 Omnipotent. It is, that in making organs for which 

 physical force has been employed, the responsive power 

 of protoplasm is seen in its forming the organ not only 

 to be admirably constructed for fulfilling its purpose but 

 m proportion to the need required. 



It has not infrequently been found necessary in 

 engineering and other constructions to endeavour to dis- 

 cover methods of securing the greatest possible strength 

 with the least amount of substance and more especially 

 the least waste of force. This is called the " Principle of 

 Least Action ". 



One of the most interesting discoveries in animal 

 mechanics is that the muscles and bones are invariably 

 constructed and placed on this principle, and often secure 

 ends far more effectively and perfectly than man has 

 succeeded in doing in architectural and engineering 

 works. 



(87) 



