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inClliXli AS XATURE SriDY 29 



liminary study pupils may be directed to take a hand mirror and 

 examine the mouth cavity. The effort here should be to have the 

 pupils discover and describe the dift'erent structures found in the 

 mouth. It will help to motivate this study if it be turned into a 

 kind of contest to see who can make the greatest number of such 

 discoveries. The pupils should be particularly directed to discov- 

 er the places in the mouth at which saliva is seen to empty into 

 it. To this end he should be directed to take a small bite of crack- 

 er, in order to start the flow of saliva, and then to note the points 

 of salivary inflow. 



(b) After the teacher has gotten from the pupils the re- 

 ports of the results of their studies, she may summarize by 

 placing on the blackboard a sketch of the figure given below (a 

 diagrammatic representation of the mouth opened so wide as to 

 show its upper and lower parts as if they were hinged back into 

 one plane). Indeed, the sketch may well be on the board when 

 the pupils' reports are called for, the final summarizing consist- 

 ing of a tabulation of the structures that may be seen. 



2. Uses of the mouth. — (a) Pinch the nose shut for a min- 

 ute or two. What use is the mouth now serving? After one has 

 been running hard for some time is it possible to get sufficient 

 breath merely through one's nose? Summarize in one state- 

 ment one of the uses of the mouth. 



(b) Give all the elementary sounds you can of each of the 

 letters of the alphabet, \\hat difference do you observe in the 

 use of the mouth in the making of the sounds of the consonants 

 and of the vowels? 



(c) Have you noticed how chickens and birds drink water? 

 Why do not people also have to throw back their heads as much 

 as birds when they drink? What use does this suggest for the 

 human mouth? 



(d) After having taken a good big bite of cracker can you 

 swallow it at once even if it is well crushed? What use have we 

 here for the mouth ? 



(e) \\liat uses does the mouth serve in connection with the 

 eating of apples and such things? 



(i) Put some raw corn starch and some cooked corn starch 

 (starch paste) in water and see if it dissolves. Could food of 

 exactly this sort be easily gotten into and carried along by the 

 blood? Put some cane or grape sugar in water and note whether 

 it dissolves or not. Now give each pupil a "bite" of raw corn 

 starch, and let him chew it but not swallow it for a minute or 



