258 VARIETIES IN THE TEETH. 



configuration of the face. This is so manifest that we 

 deem any further remarks on the subject unnecessary. 



FUNCTIONAL RELATIONS OF THE TEETH. 



The relations of the teeth, in their healthy functional 

 action, are varied, and are of great importance. They are, 

 in the first place, the immediate instruments in mastica- 

 tiona process forming one of the essential and prelimi- 

 nary steps in the function of digestion. By the incisors 

 the food is divided ; by the canine it is torn in pieces ; and 

 by the molars it is compressed, triturated, and reduced to 

 still smaller fragments adapted to the digestive powers of 

 the stomach. 



The teeth also form a wall or hedge, nicely suited to 

 retain the saliva and other fluids in the mouth. They aid 

 in articulation. All know how the loss of the teeth affects 

 the pronunciation ; how the sounds are less clear and dis- 

 tinct, and speech becomes often fatiguing, difficult, and 

 unintelligible. The incisors are of more importance in 

 articulation than any others; next in order are the ca- 

 nine ; and lastly, the molares. 



They also conduct impressions to the brain, by trans- 

 mitting them to the fifth and auditory nerves; and, finally, 

 in some of the lower animals they form the principal 

 weapons of defence, as well as of attack. 



The teeth are connected, directly or indirectly, with the 

 whole body, and all its organs and functions. We there- 

 fore postpone any further remarks on their relations, till 

 the several organs shall have come under examination. 



VARIETIES IN THE TEETH. 



These varieties are multiplied, and have been arranged 

 in reference to the age, the individual, and the race. 



Under the head of development, much has already been 

 said as to the appearance of the teeth at different ages. 

 We will therefore simply remark, in the language of Mr. 

 Blandin: "In the very young child the crown is formed 

 before the ossification of the root commences. At an age a 



