226 Mr. J. H. Gnrnoy on the [This, 



enemies by power of smell, or by sight, or, as some suppose,, 

 by a nameless faculty unknown to human beings. It is 

 curious that so important a matter should be still unsettled, 

 but there are many other problems in Natural History 

 equally obscure which will have to be solved before the 

 economy of animal life is fully understood. 



When comparing one branch of the Animal Kingdom 

 with another, it is often the custom (although not always a 

 safe one) to reason by analogy that such and such a property 

 is possessed in degree by all vertebrates or by none. If we 

 argue thus, and compare birds with mammals and other 

 animate creatures which are endowed with scent, it seems 

 reasonable to suppose that they also should be similarly 

 favoured with the possession of an organ of such great 

 utility. Of the existence of a highly-developed scent in the 

 mammals there can be no shadow of doubt ; all competent 

 sportsmen and naturalists alike admit its presence in deer 

 and carnivorous animals in the highest degree. That fishes 

 possess the sense of smell has long been suspected, and is 

 now fully acknowledged *. Butterflies and moths, or at 

 all events some of them, are credited with the enjoy- 

 ment of the faculty of scent, or something which answers 

 to it, of which many instances have already been published. 

 Enough, therefore, has been advanced to show the proba- 

 bility of birds having scent of some kind, but before entering 

 upon the subject, it will be judicious to clear the way by 

 considering the three kindred senses of sight, hearing, and 

 touch, all of which are faculties very liable to be confounded 

 with scent, and which have been repeatedly confused with it. 



To begin with sight, it is at once evident that it is impos- 

 sible to form an adequate conception of the acuteness of 

 vision which birds possess if we merely take our own faculty 

 as a standard of comparison. Most certainly the sense of 

 sight in man is little more than rudimentary when compared 

 with its development in birds. A thousand examples occur 

 to the mind immediately. What shall we say can be more 



* See Sheldon on the Dog-fish. 'Journal of Experimental Zoology,' 

 1911, p. 61. 



