DIVISIONS OF THE ANIMAL KINGDOM. Ixv 



mit to their descendants so as to constitute varieties, are, we 

 have seen, those of the body ; but the mechanism of the 

 body reacts upon the mind, and faculties which we term 

 mental are therefore transmissive. No one can doubt that 

 instinct is due to the mechanism of the nerves, and that 

 even the higher attributes of reason are due to the develop- 

 ment of the nervous system in the brain. But we can ob- 

 tain, by breeding, animals with crania of different size and 

 form, and consequently, with brains of different capacity and 

 powers. Thus we can produce, by exercise, and by selection 

 of the parents, a dog, whose cranium shall be small and flat, 

 corresponding with the elongation of the muzzle, and who 

 shall possess different propensities from another, whose brain 

 being rounder, is larger, and who is enabled to exercise facul- 

 ties for our preservation and defence, which we cannot dis- 

 tinguish from reason. 



The Hog, we have seen, communicates to his posterity, 

 along with his change of form, instincts and habits as diffe- 

 rent from those existing in the natural state as if he had be- 

 come a new species. From being a nocturnal animal, he has 

 acquired a desire to seek his food during the day, and, from 

 being solitary, he has become social, so that the male never, 

 in a state of the utmost liberty we allow him, separates from 

 his fellows of the herd. The subjugated birds convey to 

 their descendants a new set of habitudes and propensities : 

 they lose the once irresistible desire to retire in single pairs, 

 and bring up the young apart, and become entirely polyga- 

 mous. The greyhound, whose nose is small, and his body 

 fitted for rapid motion, conveys, with the conformation of 

 his organs, the desire of capturing his prey by speed alone. 

 A puppy greyhound will, the first time he springs a covey of 

 partridges, dash after them at speed; while the young pointer, 

 with the great development which has been communicated to 

 his nasal organ, will stand as if entranced, nay, if of a highly 

 cultivated breed, will couch upon the ground like the parents 



