196 EVOLUTION IN BIOLOGY VI 
Nevertheless, though the conceptions originally 
denoted by “evolution” and “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 Indiwidual. 
No exception is at this time, known to the 
general law, established upon an immense multi- 
tude of direct observations, that every living thing 
