SCENT 369 



that our sense of smell is very coarse compared with 

 that of many animals ; the example of the fox-hound will 

 at once occur. Even among normal human beings the 

 sense of smell is much more variable than are the senses of 

 hearing and sight. Fabre has shown that the olfactory 

 sense of moths is infinitely more delicate than ours. Moths 

 liberated at a distance of several hundred yards from, 

 and out of sight of, a honeysuckle bush flit straight 

 to it. 



Such exact knowledge as we possess is again due to the 

 work of von Frisch (19 19), and is again confined to the case 

 of the honey bee. The rather unexpected result of a long 

 series of experiments was that the bee's sense of smell is 

 essentially the same as our own, both in its acuteness and 

 in its power of distinguishing between different scents. 

 Bees which had been drilled to oil of orange could pick out 

 this scent with complete accuracy from forty-three other 

 ethereal oils. In addition to the oil of orange, they were 

 attracted only by oil of citron and oil of bergamot, two 

 essences of similar derivation, which, to our sense also, 

 have scents similar to that of the orange. There are certain 

 pairs of substances which, with very different chemical 

 constitution, have for us similar scents, e.g. isobutyl benzoate 

 and amyl salicylate ; such pairs tend to be confused by the 

 bee too. In one particular the bee's sense seems to be 

 sharper than ours ; the insect can pick out a particular scent 

 from a mixture better than we can. Von Frisch was unable 

 to show that certain inconspicuous flowers, which are visited 

 by bees, and are to us scentless, such as those of the wild 

 vine or the red currant, are scented for the bee. Visits to 

 such flowers seem to be made easy by the fact that they 

 always occur in masses. When bees were drilled to colour 

 and scent simultaneously, and then offered the two attrac- 

 tions separately, colour only was perceived from a distance, 

 even when the scent was very strong and a breeze carried it 

 to the bee. The general conclusion is that colour is the 

 guide to the flower, and that scent is useful in enabling the 

 bee, flying among many flowers of similar colours, to pick 



2 B 



