Heredity of Instincts. 1 5 



Such are the admitted characters of instinct Though none 

 of them is out of the reach of minute criticism ; though none 

 of them is absolutely true, still they are sufficiently exact to serve 

 to distinguish instinct from all other psychological phenomena. 



Instinct, so defined, is, beyond all question, transmissible, and 

 subject to the law of heredity. The animal inherits the psychical 

 dispositions, no less than the physiological constitutions of its 

 parents. The naturalist takes account of the former character- 

 istics, as well as of the latter. In his eyes it is as essential for the 

 bee to extract the pollen of flowers, construct cells and in them 

 deposit her honey, as for her to possess mandibles, six feet, and 

 four wings. A worker-bee with the instincts of an ant would 

 appear to him as strange a thing as a bee with wing-sheaths and 

 eight feet Every animal has two chief functions one, nutrition, 

 which preserves the individual ; another, generation, which pre- 

 serves the species. The latter transmits instincts together with 

 physical forms generation is moral as well as material. The 

 beaver transmits to its young its anatomical and physiological 

 characters as a rodent mammal, its constructive instincts, and 

 architectural talent. 



Thus we find at the outset a vast number of psychological facts 

 instinctive actions, strictly subject to the laws of hereditary trans- 

 mission. It needs no long reflection to see how large is the 

 domain of instinct : the Invertebrata seem to be completely re- 

 stricted to this form of mental activity. In the sub-kingdom of the 

 Vertebrata, the inferior classes, such as the Fishes, Batrachians, 

 Reptiles, Birds, have oftentimes no other means save instinct, of 

 supporting life, of attack, defence, and recognition of enemies. 

 Finally, among Mammals, and even in Man, instinct gradually 

 diminishes, but never entirely disappears. Its domain, therefore, 

 is co-extensive with animal life ; and this vast domain is governed 

 by the laws of heredity. 



Since it is an evident fact, universally admitted, that heredity is 

 the invariable rule of the transmission of instincts, we need not 

 cite instances to confirm our position. The tenacity of instincts is 

 so great, and their hereditary transmission so certain, that some- 

 times they are found to outlive for centuries the conditions of life to 

 which they are adapted. ' We have reason to believe,' says Darwin, 

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