ORGANS OF PERCEPTION. 209 



arc likewise classified, according to the effects which they 

 produce immediately upon the organ or the feelings in gene- 

 ral ; thus, we have pungent, nauseous, and fragrant smells. 

 In many cases, however, we are compelled, in describing an 

 odour, to compare it with that which is emitted by some well 

 known substance. Thus, we say, sulphureous, vinous, 

 alliaceous, musky, in reference to the smell of burning sul- 

 phur, wine, garlic, or musk. 



This sense gives us information of the presence of odor- 

 ous bodies, and, in many cases, of their position. It is, 

 however, more extensively employed by animals, to distin- 

 guish one body from another when contiguous, especially 

 the different kinds of food. It informs us of many of the 

 changes which take place in bodies by heat, light, or mois- 

 ture, and thus serves the purpose of a chemical test. 



The sense of smell contributes greatly to our enjoyments, 

 in our anticipations of food, and in the pleasure derived 

 from perfumes. In man, the organs of smell are more 

 developed in the savage than in the civilised state. In the 

 latter, multitudes destroy the utility of this sense, as the 

 mean of procuring information or pleasure. Other mam- 

 miferous animals derive great pleasure from this sense, as 

 is exhibited by the fondness of dogs to putrid substances, 

 against which they delight to rub themselves, and of cats 

 to particular plants. 



From the difficulty of characterising the different kinds 

 of smells, and of recollecting the particular sensations which 

 they excite, the information communicated by this sense, 

 though varied, is seldom to be relied on with much confi- 

 dence. The smell of one body may be disguised by the 

 presence of another, even when small in quantity, as may 

 be seen to a great extent in the deceptions of modern 

 cookery. 



VOL. i. o 



