148 THE POPULAR SCIENCE MONTHLY. 



smell displayed in its highest degree of power and perfection. Among 

 ruminants, some pachyderms, and particularly among carnivorous 

 mammals, the olfactory membrane attains the keenest sensitiveness. 

 Buffo n has described these animals with extreme exactness, in say- 

 ing that they smell farther than they see, and that they possess in 

 'their scent an eye which sees objects not only where they are, but 

 even wherever they have been. The peculiarity of scent in the dog 

 is too well known to need more than an allusion. 



If we can hardly give faith to those ancient historians who relate 

 that vultures were attracted from Asia to the fields of Pharsalia by 

 the smell of the corpses heaped together there after a famous battle, 

 yet we must accept the assertions of naturalists so well qualified to 

 observe as, for instance, Alexander von Humboldt. The latter relates 

 that in Peru, and other countries of South America, when it is intended 

 to take condors, a horse or cow is killed, and that in a short time the 

 smell of the dead animal attracts a great number of these birds, though 

 none had before that been seen in the country. Other more extraordi- 

 nary facts are told by travelers. These must usually be received only 

 with the greatest caution, because in most cases the sense of smell 

 gains credit for what is due to the sense of sight, which, with these 

 birds, is very keen and far-reaching. Yet, making allowance for ex- 

 aggeration, it must be admitted that these animals have a very highly- 

 developed sense of smell. Scarpa, who has made admirable researches 

 on this subject, found that they refuse food which is saturated with 

 odorous substances, and, as an odd instance, that a duck would not 

 swallow perfumed bread till after it had washed it in a pond. The 

 waders, which have the largest olfactory nerves, are also those birds 

 that display the greatest keenness of scent. Reptiles have very large 

 olfactory lobes, leading us to believe that they discern odors readily, 

 but at present we know little of the impressions they are sensitive to 

 in this respect. Fish also have an olfactory membrane. Fishermen 

 have always remarked that they may be attracted or driven off by 

 throwing certain odorous substances into the water. Sharks, and 

 other voracious fish, collect in crowds and follow from very far about 

 a body thrown into the sea. It is even said that, when blacks and 

 whites are bathing together in latitudes where these fish abound, they 

 particularly single out and pursue the more strongly odorous blacks. 

 Nor are the Crustacea indifferent to emanations which act on the 

 olfactorv nerve. The method used for attracting and taking erabs 

 is familiar. 



Regarding the lower animals we have only still more uncertain 

 information, except as to insects. Entomologists maintain that scent 

 is very delicate in most insects, and rely on plausible conjectures on 

 this subject, but they do not as yet know what the seat of the sense 

 oi smell in insects is. When meat is exposed to the air, in a few mo- 

 ments flies make their appearance in a place where none had before 



