112 A BOOK OF INSECTS 



most readily when the substance concerned is biting or 

 astringent in property. In other words, the insect appears 

 to feel its food rather than taste it. This is precisely what 

 one would be led to infer from a knowledge of insect 

 anatomy. The sense of taste, as possessed by mankind 

 and the higher animals, implies the possession of certain 

 nerves in intimate association with those which convey 

 olfactory impressions to the brain. People who lack the 

 sense of smell are also deficient in the sense of taste. For 

 some reason the nerves of taste will not perform their 

 functions unless they are en reimport with the nerves of 

 smell. If we compress the lobes of the nostrils so that 

 breath can only be drawn through the mouth, and proceed 

 to eat some sugar or honey, we find that no matter how 

 closely we may concentrate our mind upon our palate, 

 our ability to detect sweetness is in abeyance. But if, 

 still holding the nose, we substitute salt or alum for a 

 sweet substance, the nerves of the mouth at once convey 

 definite impressions to the brain. It is evident, however, 

 that these impressions are more nearly akin to a sense 

 of touch, than to one of taste. We seem to feel the 

 contact of the salt or alum with the palate very much as 

 we should feel a drop of vitriol applied to the back of 

 the hand. 



By some such means, perhaps, an insect is able to 

 determine in a rough and ready fashion the nature of 

 a substance which it has taken into its mouth ; but its 

 powers of discrimination seem to be limited and incon- 

 gruous. Will found that ants refused honey with Avhich 

 a very little glycerine had been incorporated ; but when 

 Forel offered a concoction of honey and phosphorus to 

 ants, they ate it gieedily, to their own undoing. In 

 similar circumstances man would be able to detect the 

 phosphorus, but not the glycerine. 



