INSTINCT. 227 



CHAPTER VIIL 



INSTINCT. 



Instincts Comparable with Habits, but Different in Their Origin — 

 Instincts Graduated — Aphides and Ants — Instincts Variable — 

 Domestic Instincts, Their Origin — Natural Instincts of the Cuckoo, 

 Molothrus, Ostrich and Parasitic Bees — Slave-making Ants — 

 Hive-Bee, its Cell-making Instinct — Changes of Instinct and 

 Structure not Necessarily Simultaneous — Difficulties of the Theory 

 of the Natural Selection of Instincts — Neuter or Sterile Insects — 

 Summary. 



Many instincts are so wonderful that their development 

 will probably appear to the reader a difficulty sufficient to 

 overthrow my whole theory. I may here premise, that I 

 have nothing to do with the origin of the mental powers, 

 any more than I have with that of life itself. We are con- 

 cerned only with the diversities of instinct and of the other 

 mental faculties in animals of the same class. 



I will not attempt any definition of instinct. It would 

 be easy to show that several distinct mental actions are 

 commonly embraced by this term ; but every one under- 

 stands what is meant, when it is said that instinct impels 

 the cuckoo to migrate and to lay her eggs in other birds' 

 nests. An action, which we ourselves require experience 

 to enable us to perform, when performed by an animal, 

 more especially by a very young one, without experience, 

 and when performed by many individuals in the same way, 

 without their knowing for what purpose it is performed, is 

 usually said to be instinctive. But I could show that none 

 of these characters are universal. A little dose of judg- 

 ment or reason, as Pierre Huber expresses it, often comes 

 into play, even with animals low in the scale of nature. 



Frederick Cuvier and several of the older metaphysicians 

 have compared instinct with habit. This comparison gives, 

 I think, an accurate notion of the frame of mind under 

 which an instinctive action is performed, but not necessarily 

 of its origin. How unconsciously many habitual actions 

 are performed, indeed not rarely in direct opposition to our 

 conscious wilU yet they may be modified by the will or 



