INTRODUCTION 



THE EXTERMINATION OF SPECIES 



PERHAPS few readers are aware (unless they 

 be experienced and professed zoologists) 

 how very sensitive species are to any changes in 

 their surroundings : on the one hand, quick to take 

 advantage of anything in their favour; on the 

 other hand, as readily injured by adverse conditions. 

 These latter may be of the most varied character, 

 and make their influence felt in a very complicated 

 or indirect manner, the relations not only between 

 one species and another, but with their environ- 

 ment, being most complex. Many instances might 

 be given to illustrate how complex are the relations, 

 not only of one species to another, but to the 

 environment of those species, or, in other cases, to 

 the utter dependence for existence of species upon 

 their neighbours. During the lapse of unnumbered 



