196 EVOLUTION IN BIOLOGY vi 



Nevertheless, though the conceptions originally 

 denoted by " evolution " and (i development " were 

 shown to be untenable, the words retained their 

 application to the process by which the embryos of 

 living beings gradually make their appearance ; 

 and the terms " Development/' " Entwickelung," 

 and "Evolutio," are now indiscriminately used for 

 the series of genetic changes exhibited by living 

 beings, by writers who would emphatically deny 

 that " Development " or " Entwickelung " or 

 " Evolutio," in the sense in which these words 

 were usually employed by Bonnet or by Haller, 

 ever occurs. 



Evolution, or development, is, in fact, at present 

 employed in biology as a general name for the 

 history of the steps by which any living being has 

 acquired the morphological and the physiological 

 characters which distinguish it. As civil history 

 may be divided into biography, which is the history 

 of individuals, and universal history, which is the 

 history of the human race, so evolution falls 

 naturally into two categories the evolution of the 

 individual, and the evolution of the sum of living 

 beings. It will be convenient to deal with the 

 modern doctrine of evolution under these two heads. 



I. The Evolution of the Individual. 

 No exception is at this time, known to the 

 general law, established upon an immense multi- 

 tude of direct observations, that every living thing 



