80 SENSE OF TASTE, AND OF SMELL. 



18. Most animals have very imperfect instruments of touch, 

 and, in general, the greater part of the surface of their bodies is 

 slightly or not at all sensible, on account of the hairs, feathers 

 scales, and other hard parts, with which their skins are covered. 



OF THE SENSE OF TASTE. 



19. Taste is a sense which makes us acquainted with the savor 

 or taste of substances 



20. Like touch, taste is exercised by contact only. Its seat is 

 in the mouth. 



21. The parts of the mouth where this peculiar kind of sensi- 

 bility resides are, the edges of the tongue and the arch of the 

 palate. 



22. All substances are not sapid ; those which are not soluble 

 in water seldom are. 



23. In order to act upon the sense of taste, it is necessary that 

 the sapid substances which the animal introduces into its mouth, 

 should be dissolved by the fluids poured into this cavity by the 

 salivary glands, or by some other liquid. It is in a state of solu- 

 tion, that savors are perceived by the nerves of taste, which are 

 spread out upon the surface of the tongue, and which transmit to 

 the brain the impressions of this sense. 



OF THE SENSE OF SMELL. 



24. The sense of smell reveals to us the existence of odours 

 and enables us to appreciate them. 



25. Odours are produced by extremely fine particles, which 

 escape from odorous substances, and which are diffused in the 

 air like a vapour. 



26. That odours may act upon the sense of smell, the odoriferous 

 particles must come in contact with the surface of the organ 

 wherein this sense is seated. 



27. The sense of smell is exercised in a peculiar apparatus, 

 called the nasal fossae. 



18. Are most animals well supplied with organs of touch ? 



19. What is taste? 



20. VV here is the sense of taste situated? Can this sense be exercised 

 without contact ? 



21. What parts of the mouth are endowed with the sense of taste? 



22. Are all substances sapid ? 



23. What conditions are necessary to operate on the sense of taste " 



24. What is the sense of smell ? 



25. How are odours produced ? 



26. What is a necessary condition in order to act upon the sense of 

 mell ? 



27 Where is the *ense of smell situated? 



