SENSE OF TOUCH. 11 



for smelling 1 , and the lower pair for tasting; while 

 Lehmann says, that " whoever undertakes to deny 

 that they are organs of touch, proves thereby that he 

 has not observed living insects*." Cuvierf and Du- 

 meril J express a similar opinion, supported chiefly by 

 the observation, that most insects, when they walk, 

 apply their palpi incessantly, or very often, to the 

 surface upon which they are moving ; while spiders 

 sometimes employ them as legs, and scorpions as 

 hands. They are always put in great activity when 

 the insect is feeding. 



To as the most probable opinion appears to be, 

 that the palpi may be used somewhat in the same 

 way as we employ our lips and tongue, both as in- 

 struments of touch and of taste ; their situation near 

 the mouth suggesting this, though they are otherwise 

 little analogous in site or structure. This opinion is 

 supported by the consideration that one of the chief 

 employments of insects being the search after food, 

 they are thence led to apply their palpi incessantly 

 for its discovery, and also for ascertaining its capa- 

 bility of being consumed, should the discovery be 

 originally made by means of smell. In this respect 

 insects act much in the same manner as the human 

 infant. Every body must have remarked, that a 

 young child carries every thing to its mouth, whether 

 it be hungry or not, and the only design of this 

 seems to be the examination of the object. We may 

 often, indeed, see a child pressing its gums with 

 whatever comes in its way, to allay the uneasy sen- 

 sations occasioned by the protruding teeth; but even 

 when this is not the case, it carefully tries every 

 thing both with the mouth and with the hands, hold- 

 ing the object at different distances from the eye, 



* De Sensibus Externis, page 38. 



t Anatomic Com par. ii. 676. 

 J Considerations generates, p. 9. 



