154 ANSWERS TO PRACTICAL QUESTIONS 



18. Wliy should a painter avoid getting paint on the 



palm of his hand ? 



(See Physiology, p. 62.) 



19. Why should we not use the soap or the soiled towel 

 at a hotel ? 



Because of the danger of contracting disease through the 



absorbents of the skin. (See Physiology, p. 62.) There is a 



similar danger in using a hair-brush or a comb at a barber 

 shop. 



20. Wliich teeth cut like a pair of scissors ? 



The "back teeth," as we commonly call them, when moved 

 laterally, cut somewhat in this way. In chewing the food, all 

 the "front teeth" act like scissors, as may be readily seen by 

 noticing their movements. 



21. Which teeth cut like a chisel? 



The incisors, or four front teeth of each jaw, have knife 

 edges ; the canine teeth have wedge-shaped edges ; the bicus- 

 pids and molars have broader crowns. "We can work the jaws 

 so as to make the front teeth either pierce like wedges or cut 

 like scissors. 



22. Which should be clothed the warmer, a merchant 

 or a farmer ? 



The merchant is liable to more sudden and violent changes 

 of temperature, and his body is less likely to be hardened by 

 exposure and habit to resist them. 



23. Why should we not crack nuts with our teeth ? 



The brittle enamel is very liable to crack, and once broken 

 can never be restored. 



24. Do t he edges of the upper and lower teeth meet ? 



(See Question 21.) 



25. Wlien fatigued, should you take a cold bath ? 



Certainly not. The system is not vigorous enough to pro- 

 duce a reaction, and the effect might be dangerous. 



