NATURAL HISTORY. 



87 



"Soon the sagacious brute, his curling tail 

 Flourished i.i air, lovv bending, plies around 

 His busy noe, the ^teaming vapour snuit's." SOMEKVILLE. 



country of Scotland, they were formerly much employed for such uses, but at present 



the race has become almost forgotten. 

 In the countries of South America, the 

 Spaniards employed fierce dogs to aid 

 them in conquering the Indians, but it 

 is not certain that the dogs, trained by 

 them to this cruel business, belonged 

 to the present variety. 



All the varieties of hound, however, 

 have much sagacity, and most of the 

 larger and stronger breeds have great 

 acuteness of scent, and might, without 

 much difficulty, be trained to act as 

 bloodhounds. 



268. Why is the sense of smell so fwuie in dogs ? 



The olfactory nerve in the horse, the dog, the ox, and the swine, is 

 the largest of all the cerebral nerves, and of much greater compara- 

 tive bulk in the quadruped than in the human being. The sense 

 of smell, in proportion to the size of the nerve upon which it depends, 

 is still more acute. The relative size of the nerve bears an invari- 

 able proportion to the necessity for an acute sense of smell in the 

 various animals large in the horse, compared with the olfactory 

 nerve in the ox, which is sent into the fields to shift for himself 

 larger still in the swine, whose food is buried under the soil, or 

 deeply immersed in refuse and still larger in the dog. 



269. Why do dogs lose their scent for game-birds during the 

 season of incubation? 



It is a common notion that this arises from some temporary 

 defect in the organ of smell of the dog ; but it would appear more 

 probable that birds lose, or rather do not emit, scent during the 

 time in question, and this may be owing to the habits or condition 

 of the birds being changed during the period of incubation. In 

 this may be perceived a wise and merciful provision of nature to 

 protect the birds from harm during this trying and important 

 season. 



