PERMANENT TEETH. 749 



Causes which may Hasten or Retard the 

 Appearance of the Permanent Teeth. 



It is generally considered, that thoroughbred horses and those 

 which are fed from an early age on " hard food," shed their milk- 

 teeth sooner than under-bred animals and those that are brought 

 up on green fodder. Toussaint, Goubaux and Barrier are of 

 opinion that neither breed nor food has any influence in this res- 

 pect. If this be the case, horses differ therein from horned cattle j 

 for a two-year-old Shorthorn which has been highly fed, shows 

 as a rule, the same " mouth " as an oTdinary ox of two^and-a-half 

 years. As the chief function of the incisor teeth is the prehension 

 and division of food that oft'ers a certain amount of resistance to 

 its removal from the place it occupies, or to its entrance into the 

 mouth, it is reasonable to conclude that horses which have to graze 

 on grass of a dry nature, or to consume forage that requires a good 

 deal of cutting, will wear out their incisors, especially, their front 

 and middle ones, quicker than animals that are fed, principally, on 

 corn and " choiD,'' which demand but little aid from the incisor 

 teeth for their prehension and division. This conforms to what 

 I have been told concerning the rapid wear of the incisors of horses 

 which are fed, in some districts of America, on sugar-cane as a part 

 of their fodder. Bizard and Traeger have remarked that the 

 fact of mares which have milk-teeth, being in foal, considerably 

 (say, for a year or more) delays the fall of these teeth and the 

 appearance of the permanent ones. I have seen the same thing 

 occur in cases of osteoporosis (p. 262). 



The fraudulent practice of extracting certain of the milk incisors, 

 in order to hasten the appearance of the permanent ones, may be 

 successful in its object to an extent of two or three months, at the 

 farthest. It appears, that if the operation be performed too long, 

 say, more than six months, before the usual fall of the temporary 

 teeth, the result is not " advanced " in any way ; for the resulting 

 wound soon closes up, and leaves a hard soar. To be effectual, it 

 should not be done more than three months before the natural 

 fall of the teeth. In England, we frequently see that it has been 

 performed on four-and-a-half-year-old mouths, in order to make 

 them resemble those of five-year-old animals. The fraud is easily 

 recognised from the fact that the central or lateral permanent in- 

 cisors, as the case may be, do not show wear commensurate with 

 the absence of the milk-teeth which have been removed. Also, the 

 extent of the eruption of the replacing teeth is, often, not sufficient 

 to account for the fall of the milk-teeth which preceded them. 



