IN HYGIENIC PHYSIOLOGY. 199 



They prevent the entrance of dust and other impurities. 

 They are also exceedingly delicate in all sensations of touch. 



9. What use does the nose subserve in the process of res- 

 piration ? 



It warns us of noxious gases, sifts out impurities, and 

 tempers the air before it enters the delicate respiratory organs. 



10. Why do we sometimes hold the nose when we take 

 unpleasant medicine ? 



(See Question 6.) 



11. Why is the nose placed over' the mouth ? 



As a sentinel at the gate-way to the stomach and the lungs. 



12. Describe how the hand is adapted to be the instru- 

 ment of touch. 



Its isolation at the extremity of the movable arm, the mo- 

 bility of its different parts, and the delicacy of the sensation 

 at the tips of the fingers, exquisitely adapt the hand to be the 

 instrument of touch. 



13. Besides being the organ of taste 9 what use does the 

 tongue subserve ? 



It aids in the mastication of the food and in speech. 



14=. Why is not the act of tasting complete until we 

 swalloiv ? * 



Because the organ of taste is located especially in the back 

 part of the tongue and the soft palate. 



15. Why do all things have the same flavor when one's 

 tongue is fi furred " by fever ? 



They are really tasteless. The tongue is then dry, and 

 there is no saliva to dissolve and carry particles of the food 

 into the cells covering the nerves of taste. 



16. IVJiich sense is the more useful, hearing or sight? 



(See Wonders of the Humo.n Body, p. 201,) 



"The sight speaks more directly to the intelligence; it en- 

 larges the field of thought, it gives birth to precise notions of 

 light, of form, of extent ; and it permits the communication 



