MENTAL QUALITIES OF THE HORSE. 



time. Ideas, we must remember, are no more retained 

 in the mind than are sounds in the phonograph. Habits 

 are thus formed in the individual, and by the principle 

 of heredity are transmitted to the offspring as instincts. 

 We may define an instinct as a habit which has become 

 hereditary and automatic, and which can consequently 

 be exercised without teaching, imitation, or experience. 

 Or we might regard instinct, in its collective sense, as 

 hereditary memory. Granting, as we can scarcely help 

 doing, the truth of the principle of evolution, we must 

 admit the existence of mental progress by means of 

 consciousness and association of ideas among the lowest 

 forms of animal life, if we prove it, as we can amply do, 

 among the higher animals. 



While giving full weight to the respective influences 

 of the principle of the survival of the fittest, and that 

 of selection, I think w^e must admit that instinct may 

 become greatly modified through generations by the in- 

 fluence of the association of ideas. Thus, there have been 

 frequent instances of the wild birds of recently-discovered 

 islands evincing extremely little fear of man on his first 

 appearance ; although they gradually acquired it as an 

 instinct under new influences later on. The Samoan 

 tooth-billed pigeon, which, before that island was brought 

 under the influence of Western civilisation, used to sleep 

 and breed on or close to the ground, has, by the presence 

 of its imported enemies, acquired the habit of taking 

 refuge in trees, in which it now possesses the instinct of 

 roosting and building its nest. The fear of man, which 

 we have made instinctive in many animals, may by disuse 



