PHYSIOLOGY OF OLFACTION 59 



On thus introducing odorous solutions into the nasal 

 chambers of a living subject, he found that these solutions 

 were stimuli for the olfactory organs, but that they did 

 not produce the sensation ordinarily associated with 

 them. A person, however, could soon learn to associate 

 a given sensation with a particular substance and could 

 thus acquire an ability to recognize this substance, but not 

 by what would be called its proper odor. Veress, there- 

 fore, concluded that though solutions of odorous materials 

 are stimuli for the olfactory organs, they are inadequate 

 rather than adequate stimuli. It thus appears, contrary 

 to the results obtained by Weber, that the olfactory 

 organs of an air-inhabiting vertebrate can be stimulated 

 by ordinary solutions, though this form of stimulation 

 cannot be looked upon as normal. 



To deny that the olfactory organs of man and other 

 like vertebrates are stimulated by solutions, as has been 

 done by a number of workers, implies a certain lack of 

 appreciation of the actual environment of the olfactory 

 terminals. These are the olfactory hairs that project in- 

 to the coating of mucous that covers the olfactory mem- 

 brane. These hairs appear to be completely covered by 

 the mucus and should any of their lash-like ends reach to 

 the outer surface of this layer, they are certainly far too 

 delicate to project into the adjacent air; they would 

 unquestionably remain within the limits of the mucous 

 layer. Thus the olfactory hairs are at all times sur- 

 rounded by watery mucous, which is in contact on its outer 

 face with the air carrying the odorous particles. These 

 particles, as already indicated, must be caught in great 

 numbers on the moist mucous surface, absorbed according 

 to Zwaardeniaker (1918b), and, since they are in the form 



