116 LIFE IN NATURE. 



vantage of applying not only to the formation of 

 living bodies, in so far as it is affected by condi- 

 tions arising within themselves, or by resistances im- 

 mediately operative on them in their expansion ; it is 

 capable of including, when viewed in its wider 

 aspects, all the external forces which are concerned 

 in determining their forms. For all those forces 

 have themselves arisen under the law of least resist- 

 ance. In order to bring them within the same 

 formula, we need only extend our thought and take 

 into our regard a wider sphere. The resistances we 

 have to consider are not only those which are imme- 

 diately related to the growing organism, but those 

 which exist throughout all nature. When we view the 

 living thing in its cosmical, its world-wide relations, 

 we may state in absolutely unlimited terms, that its 

 form is determined by motion in the direction of the 

 least resistance. That law has made it necessary, 

 has carried it in its bosom from the first, and in due 

 time has brought it forth. 



Mr. Herbert Spencer, in his First Principles, has 

 done me the honour to refer to my arguments on this 

 subject (as stated in the British and Foreign Medico- 



