The Origin of Organic Forms. 203 



of the living body, that result will necessarily arise 

 everywhere. The force of gravity is continually 

 active and the organism is exposed to constant strain. 

 Why then search in the distant past for a common 

 ancestry to account for similarities necessarily in- 

 volved in the problem in physics which the cosmos is 

 supposed to be engaged in solving to find the organ- 

 ized structure best adapted to the forces operating in 

 its environment, most perfectly adjusted to the me- 

 chanical conditions of organic life ? All these ela- 

 borate efforts to show how the varieties of living 

 things have arisen from the same primordial living 

 matter, is evidence that the evolution doctrine has 

 not thoroughly penetrated and shaped the thinking 

 of men of science. Every system of natural classifi- 

 cation is framed on the principle that likeness of 

 structure is evidence of community of descent. No 

 inference could be less in harmony with cosmic 

 evolution. Similarity of causes will of necessity pro- 

 duce likeness of form in organisms as well as in 

 crystals. A thorough-going acceptance of causation 

 will lead the student of nature who proceeds on the 

 principles of evolution to turn his eyes to the environ- 

 ment, to discover in dynamic law operating therein 

 the origin of resemblances as well as of differences- 

 among living things. If the vertebrate skeleton be 

 that best suited to the conditions of animal life in 

 its highest forms, there can be no sufficient ground for 

 tracing back to one vertebrate ancestor what must. 



