EVOLUTION 



505 



reproduction of organisms already existing, has always 

 been the method — ^'Omne vivum ex ovo^^ (all life from an 

 egg)) ^^omne vivum e vivo'' (all life from preexisting life). 

 438. Method of Evolution. — To recognize that evolution 

 is the method of creation still leaves unanswered the im- 

 portant question as to the method of evolution. By what 

 process was the gradual development of the living world 

 accomplished? Various hypotheses have been elaborated 

 in answer to this question. We can here only briefly 

 outline three of the most important ones. 



Fig. 388.— Louis Agassiz. (From Ballard's "Three Kingdoms.") 



I. Agassiz' s Hypothesis. — The great teacher and student 

 of nature, Louis Agassiz, beheved that the vast array of 

 plant and animal species, past and present, had no material 



