ORIGIN OF ORGANIC FORMS 291 



cannot account for these forms by starting from the 

 conditions of their individual existence, can we not 

 find the desired explanation by some other method ? 



When a historian or a politician studies the life of 

 a nation, and at a certain period of its existence comes 

 across a certain phenomenon which is not the direct result 

 of the morals and customs current at that particular 

 time, nor of the contemporary conditions of life, or when 

 he finds a very perfect and fully organised form of govern- 

 ment or society, he has recourse to historical causes in 

 order to explain them. Failing to find a ready answer in 

 the present, he looks for it back into the past. Are we 

 not entitled to use the same method for explaining pheno- 

 mena in Nature ? When an organ appears extremely well 

 adapted to its function, when we see an organism in full 

 harmony with its environment, and yet feel that the 

 contemporary influences at work upon the individual 

 organism are inadequate to explain its origin, are we 

 not then entitled to assume that this perfection did 

 not arise suddenly, but has been accomplished by a 

 slow process of historical development, and that in this 

 way the adaptation has been in the long run wrought 

 by the same physical forces as are at work at the present 

 time ? Are we not entitled to assume that physical 

 forces which may be unable to aff^ect so deeply a single 

 organism are yet able to cause a distinct change in the 

 course of a long series of generations ? 



In order to admit such an interpretation of Nature, 

 we must begin by proving two propositions : firstly, 

 that the organic world has its history; and secondly, 

 that this historical process inevitably and infallibly 

 leads to perfection. If we succeed in proving the 

 truth of these statements, we shall obviously have 

 found the general key to the explanation of the per- 

 fection of organic forms. 



Has a plant its history ? We have in passing already 



