202 CARE OF THE TEETH. 



be neglected. Cavities in these should be filled and the teeth 

 kept clean. 



Before the temporary set has gone, the first of the per- 

 manent set appear. The first of these, often called the " six- 

 year molars/' are just back of the hindermost "milk molars." 

 These should receive especial care, as they will never be re- 

 placed. Any beginning of decay in them ought to receive 

 prompt attention. 



The Care of the Teeth. The teeth need careful atten- 

 tion. They should be thoroughly brushed at least twice a 

 day, on rising and on going to bed. It would be better to 

 clean them after each meal also. If a tooth powder, recom- 

 mended by a reliable dentist, is not used, a good white castile 

 soap will serve well. It is better to use tepid water. 



If the teeth are not thoroughly cleansed, the particles 

 of food which remain will soon begin to decay. This decay 

 is caused by the growth of germs, usually some kind of bac- 

 teria; and the decay thus begun is likely to develop acids 

 which attack the limy material of which the teeth are com- 

 posed. When it is necessary to take acid medicines, care 

 should be taken not to let them come in contact with the 

 teeth. Sweet substances are very likely to decompose and 

 form acids ; so we must clean the teeth after eating candies, 

 etc. 



Toothpicks are useful in removing the larger particles. 

 But in using the toothpick care should be taken not to dis- 

 lodge fillings. 



The teeth should be examined twice a year by a dentist, 

 and any cayities promptly filled. 



Dissection of the Head of the Rabbit. Remove the 

 skin from the head. 



1. Below and back of the ear is an irregular pink mass, 

 the Parotid Salivary Gland. The duct which conveys its secre- 



