636 THE SENSE OF SMELL. 



relation of harmony and disharmony exists between odours 

 as between colours and sounds ; though it is probable that 

 such is the case, since it certainly is so with regard to the 

 sense of taste ; and since such a relation would account 

 in some measure for the different degrees of perceptive 

 power in different persons ; for as some have no ear for 

 music (as it is said), so others have no clear appreciation 

 of the relation of odours, and therefore little pleasure in 

 them. 



The sensations of the olfactory nerves, independent of 

 the external application of odorous substances, have 

 hitherto been little studied. It has been found that 

 solutions of inodorous substances, such as salts, excite no 

 sensation of odour when injected into the nostrils. The 

 friction of the electric machine is, however, known to 

 produce a smell like that of phosphorus. Bitter, too, has 

 observed, that when galvanism is applied to the organ of 

 smell, besides the impulse to sneeze, and the tickling 

 sensation excited in the filaments of the fifth nerve, a 

 smell like that of ammonia was excited by the negative 

 pole, and an acid odour by the positive pole ; whichever of 

 these sensations was produced, it remained constant as long 

 as the circle was closed, and changed to the other at the 

 moment of the circle being opened. Frequently a person 

 smells something which is not present, and which other 

 persons cannot smell ; this is very frequent with nervous 

 people, but it occasionally happens to every one. In a 

 man who was constantly conscious of a bad odour, the 

 arachnoid was found after death, by MM. Cullerier and 

 Maignault, to be beset with deposits of bone ; and in the 

 middle of the cerebral hemispheres were scrofulous cysts 

 in a state of suppuration. Dubois was acquainted with a 

 man who, ever after a fall from his horse, which occurred 

 several years before his death, believed that he smelt a 

 bad odour. 



