BLACK RAT AND BROWN RAT 27 



like what occurs between rival nations in time of 

 peace, than between rival nations in time of war. 

 Even if we accept the German notion, that they are a 

 more highly endowed, more intelligent, more indus- 

 trious and more highly civilized people than the 

 French or English or Russians, the zoological 

 analogy which seems most pertinent could be found 

 for their peaceful infiltration of Russia and France, 

 of England and the English Colonies, an infiltration 

 that has been rudely arrested by the operations of 

 war. 



Since Darwin referred to the case of rats, in his 

 chapter on the struggle for existence, an elaborate 

 and very definite story has got into literature. 

 Darwin remarked " How often do we hear of one 

 species of rat taking the place of another species 

 under the most different climates." The story which 

 has passed into almost universal acceptance is much 

 as follows. Great Britain used to be occupied by a 

 native rat, the black rat, a relatively gentle and timid 

 creature. As a collateral proof of the disposition of the 

 black rat, it is stated in many text-books on zoology 

 that the white rat with pink eyes, often kept as a pet 

 and known to be a gentle and friendly creature, is a 

 descendant of the native black rat, an albino strain 

 that has been artificially preserved by breeders. 

 Then another rat, the brown or Norway rat, reached 

 this country, probably by ships. It was a larger, 

 bolder and fiercer creature. It quickly secured a 

 foothold, attacked the black rat, drove it out of 

 occupation, and so nearly exterminated it that 

 only a few survivors have escaped destruction. It 

 is generally added that a similar process is going on 



