194 Conclusion. 



form certain actions, which are independent of indi- 

 vidual experience and are more or less the same in 

 all individuals of a given species. It is plastic, inas- 

 much as within this limited sphere, the powers of 

 cognition and appetite in the animal are given more 

 or less play for variously modifying their activities. 

 The narrower the limits within which they are con- 

 fined, the more automatically their instinct will cause 

 them to act; the wider those limits, the more plastic 

 their instinct. Both elements, automatism and plas- 

 ticity, are found in different proportions with all 

 animals from the highest to the lowest. In the lower 

 orders automatism, as a general rule, largely prevails, 

 whereas in the higher vertebrates plasticity is, on the 

 average, more predominant. Ants, too, more than 

 dogs and apes, are bound by hereditary laws to the 

 performance of certain activities. The varying 

 influence, which individual sensation brings to bear 

 upon the performance of hereditary instincts, is greater 

 and more variable in the latter than in the former, 

 and in this respect the psychic life of ants is more like 

 "automatism" than that of mammals. But, on the 

 other hand, the plasticity of the instinct is, also in 

 ants, often highly developed, and not rarely it is 

 manifested in a more quasi-intelligent form, than even 

 in the highest vertebrates. 



In the present essay we have reviewed a number 

 of the most prominent phenomena of the psychic life 

 of animals, and everywhere we found, that, what 

 modern animal psychology styles animal intelligence, 

 is met with also in ants and in many cases, in fact, in 

 a higher degree than with the highest mammals. In 



