ANIMAL DENTISTRY. 117 



the interdental space, the tirst to expose the superior ar- 

 cade and the latter to cause the horse to open the mouth 

 slightly. From this position the length, color, crusta pe- 

 trosa grooves, contiguity of the crowns, and the gingival 

 margin of the superior arcade are inspected. 



3. Without changing positions the left hand is now 

 placed gently into the interdental space as the right one 

 depresses the lower lip to expose the tables of the incisor 

 teeth to determine the shape of the tables, the absence, ex- 

 istence or size of the cups, and the shape of the internal 

 enamel surrounding the infundibula. 



4. If deemed necessary, without changing the position 

 the left hand is slipped upward along the left molar arcades, 

 to determine the number and condition of the molar teeth. 



ANOMALIES OF THE TEETH, NATURAL AND 

 ARTIFICIAL. 



Nature's anomalies in dental evolution and retrogression 

 are of such common occurrence that any set rules for the 

 determination of age will frequently mislead the diagnos- 

 tician. This is especially the case when one or two features 

 of dental growth and wear are depended upon. The com- 

 mon anomalies of the teeth are : 



(i) Anomalies of eruption. 



(2) Anomalies of the texture of the dental tissues. 



(3) Anomalies of the infundibula. 



(4) Anomalies of the cups of the infundibula. 



(5) Anomalies due to the character of the food. 



(i) Eruption of the teeth will vary slightly in dif- 

 ferent breeds and from climate and artificial influences. In 

 the well-bred horse, the thoroughbred, hackneys and Ameri- 

 can trotters, in which the development is forced from colt- 

 hood, the temporary teeth erupt several months earlier than 

 in the horse reared under more natural conditions, and the 



