SMELL. 63 



which it feeds. The immense size of its bill, which 

 is many times larger than its head, was supposed to 

 present, in its honey-comb texture, an extensive pro- 

 longation of the olfactory nerve, and thus to account 

 for its power of smelling at great distances ; but, on 

 accurate observation, the texture above-mentioned in 

 the bill is found to be mere diploe to give strength 

 to the bill. Now the eye of this bird is somewhat 

 larger than the whole brain ; and it has been ascer- 

 tained by direct experiments, that where any putrid 

 carrion was enclosed in a basket, from which effluvia 

 could freely emanate, but which concealed the offal 

 from sight, it attracted no attention from vultures 

 and other birds of prey till it was exposed to their 

 view, when they immediately recognized their object, 

 and others came rapidly from different quarters of 

 the horizon, where they were invisible a few minutes 

 before. This sudden appearance of birds of prey, 

 from immense distances, and in every direction, how- 

 ever the wind may blow, can only be accounted for 

 by their soaring to an altitude. In this situation 

 their prey on the ground is seen by them, however 

 minute it may be, and their appearance is merely 

 their descent from high regions of the atmosphere to 

 within the scope of our optics. II ow far these remarks 

 apply to the raven, the only bird of the vulture genus 

 that comes within our review, we leave for more 

 experienced naturalists*." 



Dr. Johnson here represents the toucan as preying 

 on carrion, a statement different from what is given 

 in books of natural history, and his remarks on the 

 nerves of smell are equally opposed to the recent 

 observations of Dr. Stewart Traill, of Liverpool f . 



" All systematic authors," says Dr. Traill, " have 

 described the bill of the genus Ramphastos as hol- 

 low. The Linnaean character even begins 4 Rostrum 

 * Medico-Chir, Review. f Linn. Trans, xi. 288. 



