390 LOUIS AGASSIZ. 



the transformation of the organs of one type 

 into those of another. The metamorphoses of 

 certain animals, and especially of insects, so 

 often cited in support of this idea, prove, by 

 the fixity with which they repeat themselves 

 in innumerable species, exactly the contrary. 

 In the persistency of these metamorphoses, 

 distinct for each species and known to repeat 

 themselves annually in a hundred thousand 

 species, and to have done so ever since the 

 present order of things was established on the 

 earth, have we not the most direct proof that 

 the diversity of types is not due to external 

 natural influences? I have followed this idea 

 in all the types of the animal kingdom. I 

 have also tried to show the direct intervention 

 of a creative power in the geographical dis- 

 tribution of organized beings on the surface 

 of the globe when the species are definitely 

 circumscribed. As evidence of the fixity of 

 generic types and the existence of a higher 

 and free causal power, I have made use of a 

 method which appears to me new as a process 

 of reasoning. The series of reptiles, for in- 

 stance, in the family of lizards, shows apodal 

 forms, forms with rudimentary feet, then with 

 a successively larger number of fingers until 

 we reach, by seemingly insensible gradations, 



