124 HUMBLE CREATURES. 



3. Is it a faculty by which animals are blindly im- 

 pelled to the performance of certain acts necessary for 

 their welfare ? 



4. Does it consist of propensities called into action 

 by sensations ? (or, what amounts to the same thing, 

 is it the result of certain sensations that give rise to 

 certain acts ?) 



Before proceeding any further, we must dispose of 

 the first theory by saying that, as we shall endeavour 

 to show the marked distinction between the reason of 

 man and that quality in the animal nature known as 

 " instinct," we cannot of course consider them iden- 

 tical. 



And now let us for a moment analyze an instinctive 

 action, and inquire how far it illustrates any of the 

 three remaining theories. 



A Flesh-fly deposits its eggs upon putrid substances, 

 in order that the grubs that proceed from them may 

 find nutriment upon such substances ; and we have 

 every reason to believe that it does this quite uncon- 

 scious of the end to be accomplished ; for some other 

 insects invariably (and the Fly sometimes) complete 

 this operation and die before the egg is hatched. 

 The insect can therefore know nothing of the object 

 to be attained by the performance of this act. 



Well, in the first place, an egg comes to maturity 

 in the body of the Fly, and, creating certain sensations 

 in the insect, it impels it to deposit the egg. This is 

 a direct act of Nature (for we shall not stay to inquire 

 whether it is " Nature " or " Nature's God " that gives 



