SENSE OF SMELL. 185 



16. The delicacy of this sense in the greyhound is most 

 astonishing. He not only tracks the hare, the fox, or the 

 wolf with unerring certainty, long after their footsteps have 

 been imprinted, but even in -a large city, he will trace the 

 progress of his master through thoroughfares and thickly 

 crowded streets, distinguishing his footsteps from those of a 

 thousand passers-by, and amidst the odorous particles emanat- 

 ing from a thousand sources. When Hispaniola was first dis- 

 covered by the Spaniards, they employed the greyhound in 

 hunting the poor natives, who, unlike the more fortunate 

 Seminoles of Florida, could find no ever-glade, no fastness, 

 no retreat, which could save them from the unerring scent 

 of these animals. 



J7. The organ of smell is universally found in birds, 

 though varying in size. Rapacious birds and waders, or 

 those that live on fish, have it more largely developed than 

 any others. Humboldt relates that in South America, when 

 the inhabitants wish to take the condor, they kill a horse or 

 cow, and in a short time, the odour of the dead animal 

 attracts those birds in great numbers, and even in places 

 where they were scarcely known to exist. Some of the 

 Roman historians tell us that vultures went from Asia to the 

 field of battle at Pharsalia, a distance of several hundred 

 miles, attracted thither by the smell of the dead. Pliny, the 

 natural historian, affirms that the vulture and the raven have 

 the sense of smell so delicate, that they can foretell the death 

 of a man three days beforehand. 



18. Mr. Audubon, however, relates two experiments to 

 show that vultures are indebted to sight rather than smell, in 

 the discovery of their prey. He stuffed a deer's skin with 

 hay, allowed it to become as dry as leather, and placed it in a 

 field ; in a few minutes a vulture made for it, attacked it, 

 tore open the stitches, and pulled out the hay. He then put 

 a dead hog into a ditch, and covered it over with care ; it 

 soon putrefied and became intolerably offensive, but the vul- 

 tures, which were sailing about in all directions in search of 



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