270 ANIMAL INTELLIGENCE 



introduction of new voluntary movements, involving 

 more and more complex co-ordinations, and from the 

 psychic aspect the manifest possession of the power to 

 use the machinery of the nervous system and muscles 

 in a way that implies the existence of a growing in- 

 telligence and will, and the careful observation of a 

 litter of puppies, as shown in my paper on the dog, 

 will impress both the physiologist and the psycho- 

 logist with the rapidly-increasing complexity of the 

 life of a young dog, a complexity in which reflex 

 and voluntary movements, instincts, intelligence, 

 emotions, and will blend in varying, but ever 

 augmenting, degrees of intricacy, with all of which 

 the rapidly -developing cortex is correlated, and, as 

 I have endeavoured to show in earlier papers, there 

 is a large amount of somatic correlation over and 

 above that of the brain, which is constant as to 

 period of development, but with variations for in- 

 dividuals and breeds. 



The rapidity of psychic development of a terrier, as 

 compared with a St Bernard, is very striking, even 

 within the first six weeks of life, but persists to 

 maturity ; and this, I have found, is correlated with a 

 decidedly slower functional development of the cerebral 

 cortex in the St Bernard. The difference in the motor 

 co-ordinations in the latter and the terrier is so striking 

 within the first six or eight weeks of life as to be 

 ludicrous. 



II. THE CAT. THE DOG AND THE CAT COMPARED. 



NEARLY all that has been said of the reflexes of the 

 dog applies, of course, to the cat. There are, however, 

 as would be expected, some that are peculiar to the cat 



