100 A NEW THEORY OF EVOLUTION. 



no support to the hypothesis, that the suc- 

 cessive steps resulted from accumulation of 

 beneficial differences, or were caused by some 

 force within the organism, or by external 

 influences. 



Fossils of various organisms, found in 

 primary formations, are in appearance the 

 same as species that still exist ; and as they 

 lived unchanged through more than one 

 geological epoch, during which they were 

 subjected to great variations in the con- 

 ditions of their existence, we conclude that, 

 if variation were a principle inherent in life, 

 or if specific variation could be brought about 

 by external conditions, these persistent races 

 should present some evidence of the effects of 

 the great changes through which they passed. 

 But as they remain unchanged, we are en- 

 titled to conclude that type is persistent in 

 organisms generally, and cannot be specifically 

 modified by external conditions ; or that some 

 organisms are modified by changes in the 

 conditions under which they live, and that 

 others are not. But this alternative would 

 be at variance with the homology that per- 

 vades Nature. 



Again, if we consult historical evidence, 

 we find that the representations of animals 

 in the Egyptian tombs 5000 years old also 



