74 SMELL, TASTE, ALLIED SENSES 



6. Empyreumatic odors; two subdivisions: odors of 



roast coffee, benzole. 



7. Caprilic odors; two subdivisions: odors of cheese, 



rancid fat. 



8. Repulsive odors; two subdivisions: odors of deadly 



nightshade, bedbug. 



9. Nauseating odors; two subdivisions: odors of car- 



rion, fasces. 



A survey of this classification shows at once that more 

 or less of it is associative and subjective and hence ar- 

 tificial, for what may be repulsive to one person may be 

 just the reverse to another. It is, therefore, not sur- 

 prising that some of the recent students of this subject, 

 as for instance Henning (1916), have advised the com- 

 plete abandonment of such arrangements and have 

 sought to establish by a thorough re-testing of odors an 

 impersonal and reasonable classification. As the re- 

 sult of an extended and judicious re-examination of odors 

 Henning has come to the conclusion that they fell into 

 six fundamental classes as follows: 



1. Spicy odors, such as those of fennel, sassafras oil, 



anise, and cloves. 



2. Flowery odors, such as those of heliotrope, cumarin, 



and geranium oil. 



3. Fruity odors, such as those of oil of orange, citro- 



nella, oil of bergamot, and acetic ether. 



4. Resinous or balsamic odors, such as those of tur- 



pentine, of Canada balsam, and of eucalyptus oil. 



5. Burnt odors, such as those of tar and pyridine. 



6. Foul odors, such as those of carbon bisulphide and 



of hydrogen sulphide. 

 Although each of these six classes, according to 



