92 COSMETICS. 



In the negro slave-market soundness of teeth is relied upon 

 as a sign of sound health and general bodily competence. 

 ' He who has lost a tooth,' wrote Haller, t may consider that 

 he has begun to die, and already taken possession of the next 

 world with part of his body.' 



Although the teeth-economy of human beings is that which 

 especially concerns us here, still, comparative examination of 

 the teeth of different animals has so much of interest that 

 one ought not to pass it by. As a general rule, all animals 

 of the mammalia class have teeth. To this, however, there 

 are some exceptions ; thus, the northern or whalebone whale 

 is devoid of teeth, though the warm-sea sperm-whale has 

 tremendous fangs, as those whom he has attacked in his fury 

 could attest. All the ant-eater tribe, again, are devoid of 

 teeth; appendages that would be useless to these animals; 

 even in the way, the habits of their life regarded. A few 

 remaining exceptions might be cited, were one to run the 

 animated kingdom through ; the rule being, as common expe- 

 rience makes known, that mammalian animals are all teeth- 

 provided. Not all, however, with teeth on the same pattern 

 and principle. Among mammals the elephant is most pecu- 

 liar for the mode of teeth formation and development. About 

 the tusks of an elephant little need be written; they are 

 simply long and large teeth, which grow pretty much after 

 the manner of other teeth. It is the short or grinding- 

 teeth of an elephant that are the most peculiar ; they are de- 

 veloped in a sort of bony trench, and in growth continually 

 move forwards. 



The teeth of rodent animals are, again, peculiar. Thus, 

 for example, if the teeth of a rat be examined, they will be 

 found to terminate each in a cutting, chisel-like edge; and 

 the arrangement of parts is such that, gnaw as much as 

 the creature will or must, the sharpness of these chisel- 

 edges can never be lessened. The result comes to pass in 

 this way : the outside surface of the tooth of a rat contains 



