It has been observed, that animals who possess the most acute smell, have the nasal organs the most extensively developed. The Ethiopians and the American Indians are remarkable for the acuteness of this sense, accounting for the wonderful power of tracking their enemies. But although we may take the peculiar organization of their olfactory organs as being partly the cause of this keen perceptibility, we must in a great measure attribute this perfection to their mode of living. Hunting and war are their chief pursuits, to which they are trained from their earliest infancy: therefore this perfection may, to a certain extent, be the result of habit; and the sight and hearing of these wanderers are as singularly perfect as their smelling. Mr. Savage relates, that a New Zealander heard the report of a distant gun at sea, or perceived a strange sail, when no other man on board could discern it. Pallas, in speaking of the Calmucks, says that many of them can distinguish by smelling at the hole of a fox whether the animal be there or not; and on their journeys and military expeditions they often smell out a fire or a camp, and thus seek quarters for the night or booty. Olaus Borrich informs us, that the guides between Smyrna, Aleppo, and Babylon, when traversing the desert, ascertain distances by the smell of the sand. That odours float in the atmospheric air is obvious; the distance at which they are perceived is incredible. The spicy breezes of Ceylon are distinguished long before the island is seen; and it is a well-known fact that vessels have been saved by the olfactory acuteness of dogs, who, to use the common expression, were observed to "sniff" the land that had not been descried. As a proof of the intimate connexion between smell and respiration, when the breath is held odorous substances are not perceived, and it is only after expiration that they are again recognised. A proof of this may be easily obtained by placing the open neck of a small phial containing an essential oil in the mouth during the acts of inspiration and subsequent expiration. Willis was the first who observed that, on placing a sapid substance in the mouth, and at the same time closing the nostrils, the sensation of taste is suspended; and this observation has given rise to the prevailing opinion that smelling and tasting are intimately related. Odour which thus accompanies taste is termed flavour; and the ingenious Dr. Prout has admirably defined the distinction between taste and flavour, and he considers the latter an intermediate sensation between taste and smell. The acuteness of the sensation of smelling in animals is such, that in many instances our observations have been deemed fabulous. The distance at which a dog tracks his master is scarcely credible; and it is strange that the ancients attributed a similar perfection to the goose. Aelian affirms that the philosopher Lycadeus had one of these birds that found him out like a dog: