SMELL. 409 



nying the capability of water to serve as the ve- 

 hicle of odorous effluvia. But as water is known 

 to contain a large quantity of air, which acts upon 

 the organs of respiration, it is easy to conceive 

 that it may also convey to the nostrils the pecu- 

 liar agents which are calculated to excite percep- 

 tions of smell. Fishes are, in fact, observed to be 

 attracted from great distances by the effluvia of 

 substances thrown into the water ; and they are 

 well known to have a strong predilection for all 

 highly odoriferous substances. Baits used by 

 anglers are rendered more attractive by being 

 impregnated with volatile oils, or other sub- 

 stances having a powerful scent, such as assa- 

 fcetida, camphor, and musk. Mr. T. Bell* has 

 discovered in the Crocodile and Alligator, a gland, 

 which secretes an unctuous matter, of a strong 

 musky odour, situated beneath the lower jaw, 

 on each side. The external orifice of this gland 

 is a small slit, a little within the lower edge of 

 the jaw; and the sac, or cavity containing the 

 odoriferous substance, is surrounded by two 

 delicate bands of muscular fibres, apparently 

 provided for the purpose of first bringing the 

 gland into a proper position, and then, by com- 

 pressing it, discharging its contents. Mr. Bell 

 conceives that the use of this secretion is to act 

 as a bait for attracting fish towards the sides of 

 the mouth, where they can be readily seized in 



* Phil. Trans, for 1827, p. 132. 



