682 ZOOLOGY. 



It would appear, then, that animals have in some slight 

 degree what we call 7nind, with its threefold divisions of the 

 sensibilities, intellect, and will. When we study animals in 

 a state of domestication, especially the dog or horse, we 

 know that they are capable of some degree of education, 

 and that they transmit the new traits or habits which they 

 have been taught to their offspring ; so that what in the 

 parents were newly acquired habits become in the descend- 

 ants instinctive acts. We are thus led to suppose that the 

 terse definition of instinct by Murphy, that it is " the sum 

 of inherited habits," is in accordance with observed facts. 

 Indeed, if animals have sufficient intelligence to meet the 

 extraordinary emergencies of their lives, their daily, so- 

 called instinctive acts, requiring a minimum expenditure of 

 mental energy, may have originated in previous genera- 

 tions, and this suggests that the instincts of the present 

 generation may be the sum total of the inherited mental ex- 

 periences of former generations. 



Descartes believed that animals are automata. Lamarck 

 expressed the opinion that instincts were due to certain in- 

 herent inclinations arising from habits impressed upon the 

 organs of the animals concerned in producing them. 



Darwin does not attempt any definition of instinct ; but 

 he suggests that " several distinct mental actions are com- 

 monly embraced by this term," and adds that " a little 

 dose, as Pierre Huber expresses it, of judgment or reason 

 often comes into play, even in animals low in the scale of 

 nature." He indicates the points of resemblance between 

 instincts and habits, shows that habitual action may become 

 inherited, especially in animals under domestication ; and 

 since habitual action does sometimes become inherited, he 

 thinks it follows that " the resemblance between what origi- 

 nally was a habit and an instinct becomes so close as not to 

 be distinguished. " He concludes that, by natural selection, 

 slight modifications of instinct which are in any way useful 

 accumulate, and thus animals have slowly and gradu- 

 ally, " as small consequences of one general law," acquired, 

 through successive generations, their power of acting in- 



