162 AGE OF THE DOMESTIC ANIMALS. 



second and third molars, which are sometimes through the gum» 

 at birth or appear immediately after birth. 



The permanent molars make their appearance in the fol- 

 lowing order : Second molar from twelve to eighteen months ;. 

 first molar from twenty- four to thirty months ; third molar at 

 thirty-six months ; fourth molar at eighteen months ; fifth molar 

 at twenty-four to thirty months ; and the sixth molar at three 

 years or later. When the rudimentary molar (wolf-tooth) 

 exists it appears about the tenth month, and is driven out of its 

 alveolar cavity, with the appearance of the first permanent 

 (fourth) molar, at the age of two years. 



Simonds claims that the molars do not show in the calf at 

 birth, and first make their appearance at the end of the first 

 month. Simonds also difiers slightly from Girard as to the 

 eruption of the permanent molars, placing the appearance of the 

 fourth molar at six months ; the fifth at fifteen months ; the 

 sixth at two years. He evidently studied on very precocious 

 cattle. Undoubtedly the eruption of the molars in cattle is 

 variable, and, owing to the trouble of examination in the living 

 animal, its careful study has been neglected. 



An annexed table shows the diversity of eruption in various 

 subjects. It will be found to vary somewhat, not only in the 

 different races of cattle, but in the families of the same race 

 which are reared under different climatic conditions and are 

 nourished more or less liberally. 



The periods of the animal's life, as indicated by the teeth, 

 form the following natural divisions : — 



1. Eruption of the temporary teeth. 



2. Wearing of the temporary teeth. 



3. Eruption of the permanent teeth. 



4. Leveling of the permanent teeth. 



5. Wearing away of the crowns. 



