PERCEPTION. 131 



of the individual prior to its own experience. We have 

 abeady seen that heredity plays an important part in forming 

 memory of ancestral experiences, and thus it is that many 

 animals come into the world with their powers of perception 

 already largely developed. Tliis is shown not only by such 

 cases as those of Galen's kid, and Preyer's chickens before 

 mentioned, but by all the host of instincts displayed by 

 newly-born or newly-hatched animals, both Vertebrate and 

 Invertebrate. This subject will be fully considered when I 

 come to treat of Instinct, and then it will be found that the 

 wealth of ready-formed information, and therefore of ready- 

 made powers of perception, with wliich many newly-born or 

 newly-hatched animals are provided, is so great and so 

 precise, that it scarcely requires to be supplemented by the 

 subsequent experience of the individual. In different classes 

 of animals these hereditary endowments vary much both in 

 kind and in degree. Thus, with mammals as a class, heredi- ^ 

 tary perception has reference in its earliest stages to the senses 

 of smell and of taste ; for while many mammals are born 

 blind, some probably deaf, and all certainly very deficient in 

 powers of locomotion, they invariably show more or less 

 perceptive powers of taste, and very frequently well-advanced 

 perceptive powers of smell. This we have already seen in 

 the case of Galen's kid, and in the case of the dog (whose 

 ancestors have depended so largely upon the perfection of 

 smell) the same thing occurs in so high a degree, that so 

 special an olfactory impression as is produced by the odour of 

 a cat will cause a litter of newly-born puppies to " putf and 

 spit."* 



Birds come into the world with better endowments of 

 perception than animals of any other class. For they are in 

 full possession of every sense almost immediately after they 

 are hatched, and, as we shall see later on, they are then able 

 to use their senses nearly as well as they are ever able to 

 use them. 



Reptiles are likewise hatched with their powers of percep- 

 tion almost as highly developed as they are ever destined to 

 become,! and the same as a rule is true of invertebrated 

 animals. 



I must now say a few words on the physiology of Percep- 



* See p. 164. t See Animal Intelligence, pp. 256-7. 



I 2 



