THE HOESE AXD ITS DISEASES. 31 



We think it very improbable that wild mules were 

 found, as hybrids are only known to be generated under 

 the influence of domestication, or, if the manner of 

 engendering mules were known to the Israelites, that 

 people probably desisted from breeding them, in conse- 

 quence of the Diyine law against their propogation ; for 

 it is said, "Ye shall keep my statutes, thou shalt not 

 let thy cattle gender with diverse kind." It is therefore 

 likely, that the mules which David and his nobles rode, 

 were imported from other countries. In Greece and 

 Cappadocia they abounded in early times. 



Teeth Characterizing the Age. 



The teeth of animals are formed or fitted for the food 

 on which they live. There are three sorts of teeth — 

 cutting teeth, canine teeth, and molar teeth. Man has 

 thirty-two teeth ; those in the front are cutting teeth, or 

 incissors, these behind, and with which he grinds his 

 food, are molar, or grinding teeth, and the sharp pointed 

 teeth on each side of the incissors, are the canine teeth. 

 The canine teeth are best seen in the mouth of the cat, 

 the dog, the lion, and some others. In each jaw of a 

 man there are four fi^ont teeth, or incissors, two canine 

 teeth (called also eye teeth), four small grinders, and 

 six huge grinders — in all sixteen teeth. Children have 

 but twenty teeth at first, or ten in each jaw ; these are 

 called milk teeth, because they appear, for the most part, 

 while the child lives on milk. The teeth of the mole 

 are fitted to crush the hard horny coverings of insects, 

 and to knaw the roots of plants where worms are found ; 

 while dogs, cats, bears, and others of this family have 

 teeth foimed for cutting the flesh on which they feed. 

 The Greenland whale has no teeth, but fibrous horny 

 plates, which are fringed, and known as whalebone. 

 Gnawing animals have two long teeth, which project 

 forward from each jaw, and which have an edge like a 

 chisel, while the horse and ass have to seize and crush 

 tlie grass and grains on which they live. Man can tell 



