"It matters not how much the effluvia may be gone off, so as enough remains to irritate the olfactory organ: for whether it be bird or beast, they try the scent in all directions, till at length they discover that which is stronger and stronger, in proportion as they proceed; and this Nature has taught them to know is the direct and obvious road to their prey, and prevents them from following a contrary course, which is naturally weaker and weaker, and what in hunting is called _heel_. This observation is confirmed by the encreasing eagerness we perceive in all animals, the nearer they approach the object of pursuit; as we see hounds and spaniels in HUNTING and SHOOTING, are the most earnest, in proportion as the scent is recent, and they draw nearer to the GAME. The same thing amongst quadrupeds, whether wild or domestic, directs the male to the female that is in season for love; and hence we see the DOG, the BOAR, the BULL, and the STALLION, when turned loose, apply their nostrils to the ambient air, and proceed accordingly. By the same medium the vermin which infest our dwellings know how to direct their operations; whether to undermine walls, eat through solid boards, cross rivers, or climb spouts; which shows how much stronger the faculty of smelling is possessed by the _brute_ than the HUMAN species; wisely ordained by NATURE, to enable them to seek their food, and propagate their species; but for which they would often perish, or have long since become extinct." SOMERVILE, seemingly anxious to explore this hidden source of instinct, conceives the SCENT (divested of the dignity of blank verse) to arise from the peculiar property of the blood; which, when the game is on foot, is so encreased in its circulation, that the "ferous particles" are propelled through the skin in perspiration, and "Leaves a long-steaming trail behind; which, by The cooler air condens'd, remains, unless By some rude storm dispers'd, or rarefy'd By the meridian sun's intenser heat: To every shrub the warm effluvia cling, Hang on the grass, impregnate earth and skies. With nostrils opening wide, o'er hill, o'er dale, The vig'rous hounds pursue, with ev'ry breath, Inhale the grateful steam, quick pleasures sting Their tingling nerves, while their thanks repay, And in triumphant melody confess The titillating joy. Thus on the air Depends the hunter's hopes."