100 COSMETICS. 



are teeth mounted on either metal or vulcanite. The metals 

 used for this purpose are gold, palladium, and sometimes plati- 

 num the only objection to which last is its extreme weight. 

 Silver, considered as a metal for dentistry purposes, would be 

 wholly objectionable, on account of the facility with which it 

 blackens when brought into contact with sulphur, or things 

 holding sulphur; an alloy of silver and palladium, however, 

 is good. In saliva there is much of sulphur ; no inconsiderable 

 amount in many varieties of food. Among condiments, mus- 

 tard teems with sulphur ; and perhaps, with the single excep- 

 tion of salt, no article of either food or condiment is wholly de- 

 void of sulphur. From all this it follows that pure silver would 

 not serve the dentist's purpose at all. Occasionally teeth are 

 filled with silver instead of gold-leaf; concerning which prac- 

 tice all the chemist can record is pity dentists don't know 

 better. 



In respect to gold, whether employed in mounting den- 

 tistry, or for any other constructive purpose, the fact need 

 hardly be explained that the noble metal is never used pure ; 

 absolutely pure gold is scarcely more rigid, hard, and mechani- 

 cally enduring than absolutely pure lead. It needs alloy to 

 give mechanical hardness and impart endurance. The gold 

 coins of this realm are composed of twenty-two parts gold to 

 two parts copper in twenty-four. Hence, in technical lan- 

 guage they are said to be twenty-two carats fine. No gold 

 for dentistry purposes should have a lower quality than twenty 

 carats ; in other words, should hold more than four parts of 

 copper or other alloy in the twenty-four. Gold-foil for filling 

 teeth should be made of absolutely pure gold; in technical 

 language, gold of four-and-twenty carats fine. 



Toothache one needs must touch on. Why the two fell 

 tortures of gout and toothache are so commonly regarded as 

 ailments absolved from pity, I know not of my own know- 

 ledge, and never found any one who did. Toothache has this 

 advantage over gout, that it is always alleviable, and that in 



