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" The external world is known to us only through our senses. 

 All that we perceive of that world, all that has an existence in it 

 for beings constituted such as we are, comes through these avenues 

 to the mind. The various influences affecting us from without are 

 modified by, and take part of their character from these senses. 

 Although we are accustomed to look upon our perceptions as the 

 exact counterparts of external objects, this is not really the case. 

 The external representative of colour, for instance, is nothing but 

 undulations of the ether which pervades all space. The sounds 

 we hear have nothing corresponding to them without us, but vi- 

 bratory movements of the atmosphere ; and the smells we perceive 

 are represented really in the outer world by unspeakably minute 

 particles of certain bodies floating in the air. It is by the correction 

 which one sense makes upon the verdicts of another, and by the ex- 

 ercise of our rational faculties on the facts brought into the mind 

 through these organs, that we have freed our primary impressions 

 of the outer world from much that is erroneous and misleading. 

 Hence, the importance of special study of the sense, both taken 

 individually and in their mutual relations. Look at the results 

 which have attended the investigations of the eye and the light 

 which appeals to it ; of the ear, and the sounds which are addressed 

 to it. It is not too much to expect that the scientific study ot 

 smell and its proper objects will lead us still further into the secret 

 recesses of nature, and furnish us with a more intimate knowledge 

 of the qualities of bodies than we now possess. This study has 

 another utilitarian aspect. The nose is the sentinel which watches 

 for the approach, and gives warning of inimical gases in the air, 

 tending to enter the lungs — the citadel of life. This sense also, 

 like the eye and ear, is the avenue for aesthetic impressions. There 

 is ample field in the domain of pleasant odours for receiving sen- 

 sations of the beautiful, enough to create a new world of feeling 

 within us. These were some of the reasons which induced me to 

 make this subject a matter of study. You have the results of that 

 study in the main in this paper. The organ of smell, proper, in 

 mammals, is situated in the superior portion of the nasal cavities. 

 It is a vascular spongy membrane, with brownish-coloured cylindrical 



