Vo THE HORSE. 



four and a-lialf years of age, tlie milk corner incisors are slied, 

 their jDlace being taken by the permanent corner incisors. 

 The milk, or temporary, incisor teeth have now all disa}> 

 peared, and the horse has a complete set of permanent incisors, 

 though the corner incisors are not, as yet, level with the 

 centrals and laterals. The corner incisors do not show their 

 full development until the horse is five years old. When a 

 young horse is in possession of its comi3lete set of permanent 

 teeth it is said to have a '" full " mouth. Until horses become 

 live-year-olds, their age is readily ascertained by the replace- 

 ment of the milk incisors by the permanent ones, as just 

 described. After a horse is five years old, its age can be told 

 by the changes occurring in the " tables " of the incisor teeth 

 in the lower jaw. The " table " of an incisor tooth is the top 

 surface, which is hidden from view Avhen the teeth are closed. 

 In these '' tables " there are originally dark-coloured marks, 

 which gradually wear away owing to the friction between the 

 upper and lower teeth, and they finally disappear almost com- 

 pletel}-. This wearing-away process of the " marks " goes on 

 very regularly. The marks in the centrals disappear first, 

 next those in the laterals become worn away, and lastly, those 

 in the corner incisors are lost. About one year's interval 

 occurs between the disappearance of the marks in the respec- 

 tive pairs of incisors. Wlien a horse is six years old, the mark 

 in the centrals has more or less worn away, but the marks on 

 the other incisors are fully apparent. At seven years old, 

 the marks in the laterals begin to disiippear, and finally, at 

 eight years old, the corner incisors also gradually lose their 

 marks. After this stage, it becomes more and more difficult 

 to tell the age of a horse. Changes still continue to occur in 

 the shape of the teeth, but these changes do not afford an 

 easy or A^ery 'satisfactory indication of a horse's age. The 

 chano-es consist in the incisors becomino: more or less triangu- 

 lar in shape at their table surface. When the horse is nine 

 years old, the tables of the centrals assume a triangular shape ; 

 a year later, that is to say, when the animal is ten years of 

 age, the lateral incisors also become triangular, and lastly, 

 at eleven vears. old the corner incisors do tlie same. Of 



