12 NATURE-STUDY LESSONS. 



13. Note the enjoyment we gain from eating that 



which pleases our taste. 



Note. — Sugar is sweet, common salt is salty or saline, sea- water is 

 brackish, pepper is pungent, alum is astringent, vinegar is sour or acid, 

 quinine is bitter, ' wild-turnip ' is acrid, turpentine is terebinthine, onion or 

 garlic is alliaceous, meal is farinaceous. The tastes of many substances 

 are named by reference to the tastes of other well-known substances; hence, 

 we say 'oily,' 'cheesy,' 'fishy,' 'like radish,' 'like mint,' 'like lemons,' 

 Many of the so-called tastes are combinations of taste, smell, and feeling. 



VI.- SMELLING. 



A. Sense of Smell. 



1. You have two unlabel! ed bottles, one of turpentine 

 and the other of water. How can you tell which each is? 



2. With eyes closed, try to name certain things used 

 for food — sugar, dried fruit, oatmeal, onions, oranges, 

 toast. 



3. By the sense of smell alone, try to distinguish 

 certain flowers. 



B. Organ of Smell. 



4. Observe the nose and note its parts. 



5. The nose is of what other use than as an organ of 

 smell ? 



6. What advantage is it that the nerves of smell are 

 in the respiratory path ? 



7. Note that the bottle of turpentine in No. i must be 



uncorked to allow a part of the turpentine to escape. 



The most powerful microscope is unable to reveal the fine particles that 

 touch the sense of smell. You smell a flower. The fragrance is agreeable, 

 but you cannot see it. The fragrance is really due to very fine particles 

 floating about in the air, and going with it into the nostrils. There are a 

 great many folds in the nose, which present a great deal of surface to the 

 fine particles. In the lining of tho nose are very fine nerves. The little 

 particles stimulate the nerves. The nerves convey the stimulus to the 

 . brain. The mind then knows it as a sensation of smell. 



C. Uses of Smell. 



8. How are you enabled to detect the presence of coal 

 gas in a house ? 



