SCREAMING COW-BIRD 109 



presents itself to the mind as to use the words of a 

 naturalist of the eighteenth century, who was also a 

 theologian and believed the Cuckoo had been created 

 with such a habit " a monstrous outrage on the 

 maternal affection, one of the first great dictates of 

 nature/' An outrage, since each creature has been 

 endowed with this all-powerful affection for the 

 preservation of its own, and not another, species ; 

 and here we see it, by a subtle process, an uncon- 

 scious iniquity, turned from its purpose, perverted 

 and made subservient to the very opposing agency 

 against which it was intended as a safeguard ! The 

 formation of such an instinct seems indeed like an 

 unforeseen contingency in the system of nature, a 

 malady strengthened, if not induced, by the very 

 laws established for the preservation of health, and 

 which the vis medicatrix of nature is incapable of 

 eliminating. Again, the egg of a parasitical species 

 is generally so much larger, differing also in coloration 

 from the eggs it is placed with, whilst there is such 

 an unvarying dissimilarity between the young bird 

 and its living or murdered foster-brothers that, un- 

 reasoning as we know instinct, and especially the 

 maternal instinct, to be, we are shocked at so glar- 

 ing and flagrant an instance of its blind stupidity. 



In the competition for place, the struggle for 

 existence, said with reason to be most deadly between 

 such species as are most nearly allied, the operations 

 are imperceptible, and the changes are so gradual 

 that the diminution and final disappearance of one 

 species is never attributed to a corresponding in- 



