45 



III. 



MIMICRY, AND OTHER PROTECTIVE RE- 

 SEMBLANCES AMONG ANIMALS. 



THERE is no more convincing proof of the truth of 

 a comprehensive theory, than its power of absorbing 

 and finding a place for new facts, and its capability 

 of interpreting phenomena which had been previously 

 looked upon as unaccountable anomalies. It is thus 

 that the law of universal gravitation and the undu- 

 latory theory of light have become established and 

 universally accepted by men of science. Fact after 

 tact has been brought forward as being apparently 

 inconsistent with them, and one after another these 

 very facts have been shown to be the consequences 

 of the laws they were at first supposed to disprove. 

 A false theory will never stand this test. Advancing 

 knowledge brings to light whole groups of facts 

 which it cannot deal with, and its advocates steadily 

 decrease in numbers, notwithstanding the ability 

 and scientific skill with which it may have been 

 supported. The great name of Edward Forbes did 

 not prevent his theory of " Polarity in the distribu- 

 tion of Organic beings in Time " from dying a 

 natural death ; but the most striking illustration of 

 the behaviour of a false theory is to be found in the 

 " Circular and Quinarian System " of classification 



