204 ANIMAL DKN'IMS'l'RV. 



with the bitting ri^g^ing of a driving horse. In the treat- 

 ment of eye affection their extraction is particularly advis- 

 able, owing to the popular prejudice against them. 



They are difficult to extract without fracture because 

 their location j^rexents direct outward traction and l)ecausc 

 of the impossibility of perfectly immobilizing the head and 

 especially the lower jaw. Their removal is accomplished by 

 first disturbing their implantation with the wolf tooth sep- 

 arator (Fig. 93) prior to the application of outward traction 

 with the forceps, or with the separator alone. 



Fig. 143. 

 Supcrmimcrary Incisors of a 6- Year-Old Gelding. 



SUPERNUMERARY TEETH. 



Definition — Teeth existing in excess of the normal num- 

 ber in any of the arcades, are designated as supernumerary. 

 'Jliey must be differentiated from wolf teeth, which are nor- 

 mal structure and from persisting temporary teeth, due to 

 displacement of the permanent tooth germ. 



Etiology — The supernumerary teeth result from the pro- 

 jection of more than one stalk from the common enamel 

 germ. This occurrence is frequent if not universal, but un- 

 der normal development, all the stalks degenerate as a chief 

 one predominates. Whenever two or more keep pace witli 

 one another until tooth development is well advanced, the 



