460 



Comparative Animal Physiology 



i< 



Fig. 149. Curves illustrating the relation between the response of Drosophila and the 

 concentration of ethyl alcohol. Solid circles, per cent males responding; t)pen circles, per 

 cent females responding; solid lines, the per cent males and females attracted; broken 

 lines, per cent males and females repelled. After Reed,"' from Dethier.'" 



fication may eventually be replaced by one which is objective and based 

 on some chemical or physical property of the stimulus. One oF the earliest 

 and still acceptable subjective classifications of odors is that of Zwaarde- 

 maker,''"' who divided odors into nine classes, with two or more subdivisions: 

 Class Subdivisions 



1. Ethereal (a) Fruit, (fo) Beeswax, (c) Ethers 



2. Aromatic (a) Camphor, (/O Cloves, (c) Lavender, 



(ci) Lemon, (e) Bitter almonds 



3. Balsamic or Fragrant («) Flowers, (fo) Violet, 



(c) Vanilla and coumarin 



4. Ambrosial 00 Amber, (f?) Musk 



5. Alliaceous («) Sulphuretted hydrogen, 



(/?) Arsine, (c) Chlorine 



6. Empyreumatic (a) Roast coffee, (fo) Benzene 



7. Caprilic («) Cheese, (fo) Rancid fat 



8. Repulsive (a) Deadly nightshade, (b) Bed-bug 



9. Nauseating or Fetid (a) Carrion, (b) Feces 



