210 CONSCIOUSNESS IN 



acuteness may perhaps rival, if it does not exceed, that of 

 any other animal whatsoever. In certain Insects with 

 enormously developed eyes, however, such as Dragonflies, 

 Sight also seems to be an all-important sense : so that 

 Smell and Sight may he said specially to guide the actions 

 of Insects, though not equally in the same species. 



The sense of Smell in Fishes, moreover, seems, accord- 

 ing to Kirby,* to be the most acute of all their senses. 



Lacepede says : " It may be called their real eye, since by it 

 they can discover their prey or their enemies at an immense dis- 

 tance ; they are directed by it in the thickest darkness, and the 

 most agitated waves. The organs of this sense are between the 

 eyes. The extent of the membrane on which the olfactory nerves 

 expand in a shark twenty-five feet long, is calculated to be twelve 

 or thirteen square feet." 



In a few Birds, such as Vultures and their allies, a mar- 

 vellously keen sense of Smell was for a long time sup- 

 posed to exist, though the observations of Darwin and 

 others make it probable that this supposition is erroneous, 

 and that the facts on which it was based may be better 

 explained by the great keenness of their sense of Sight. 

 Certainly in the majority of Birds, the olfactory sense 

 seems to be very slightly developed. 



An extremely acute sense of Smell seems, however, 

 to exist with many wild and domestic Quadrupeds. A 

 well-known instance, belonging to the former category, is 

 that of the Deer. 



Again Swainson writes,f "The scent of the American Bison 

 is said to be so keen that it is difficult for either men or dogs to 

 get near him, excepting on his leeward side; while the Camel, by 

 the perfection of the same sense, is enabled, while wandering over 



* Kirby's " History, Habits, and Instincts of Animals," vol. ii. 

 p. 278. 

 f " Habits and Instincts of Animals," p. 49. 



