244 THE RIDDLE OF THE UNIVERSE. 



answer to all the questions of creation. Even the 

 phenomena which led directly to the observation of 

 the facts of evolution — the embryology of the plant 

 and the animal, and of man — remained unnoticed, 

 or only excited the interest of an occasional keen 

 observer, whose discoveries were ignored or forgotten. 

 Moreover, the path to a correct knowledge of natural 

 development was barred by the dominant theory 

 of preformation, the dogma which held that 

 the characteristic form and structure of each animal 

 and plant were already sketched in miniature in the 

 germ (cf. p. 54). 



The science which we now call the science of 

 evolution (in the broadest sense) is, both in its 

 general outline and in its separate parts, a child of 

 the nineteenth century ; it is one of its most 

 momentous and most brilliant achievements. Almost 

 unknown in the preceding century, this theory has 

 now become the sure foundation of our whole world- 

 system. I have treated it exhaustively in my General 

 Morphology (1866), more popularly in my Natural 

 History of Creation (1868), and in its special applica- 

 tion to man in my Antliropogeny (1874). Here I 

 shall restrict myself to a brief survey of the chief 

 advances which the science has made in the course of 

 the century. It falls into four sections, according to 

 the nature of its object ; that is, it deals with the 

 natural origin of (1) the cosmos, (2) the earth, (3) 

 terrestrial forms of life, and (4) man. 



I. — MONISTIC COSMOGONY. 



The first attempt to explain the constitution and 

 the mechanical origin of the world in a simple 



