Ill LECTURES ON EVOLUTION 77 



France numerous mummified corpses of the 

 animals which the ancient Egyptians revered and 

 preserved, and which, at a reasonable computa- 

 tion, must have lived not less than three or four 

 thousand years before the time at which they 

 were thus brought to light. Cuvier endeavoured 

 to test the hypothesis that animals have under- 

 gone gradual and progressive modifications of 

 structure, by comparing the skeletons and such 

 other parts of the mummies as were in a fitting 

 state of preservation, with the corresponding parts 

 of the representatives of the same species now liv- 

 ing in Egypt. He arrived at the conviction that 

 no appreciable change had taken place in these 

 animals in the course of this considerable lapse of 

 time, and the justice of his conclusion is not 

 disputed. 



It is obvious that, if it can be proved that 

 animals have endured, without undergoing any 

 demonstrable change of structure, for so long a 

 period as four thousand years, no form of the 

 hypothesis of evolution which assumes that ani- 

 mals undergo a constant and necessary progressive 

 change can be tenable ; unless, indeed, it be further 

 assumed that four thousand years is too short a 

 time for the production of a change sufficiently 

 great to be detected. 



But it is no less plain that if the process of 

 evolution of animals is not independent of sur- 

 rounding conditions; if it may be indefinitely 



