60 



DIGESTION AND FOOD. 



The inferior incisors begin to wear by fifteen months. At 

 Fig. 27, the milk teeth are shown as seen in a puppy two or 

 three months old, whereas Fig. 28 represents them in a year- 



Fig. 27. 



Fig. 28. 



old dog At eighteen months or two years, the inferior cen- 

 tral incisors are much worn, and between two and three years 

 (see Fig. 29) the middle ones are also worn. The worn Ln- 



Fig. 29. 



cisor bears a striking contrast with the young teeth as shown 

 at Fig. 28, where the edge or border of the teeth is divided 

 into three lobes, of which the most prominent constitutes the 

 point of the tooth. " The two lateral lobes have the appear- 

 ance of notches cut on either side of the principal lobe, and 

 the union of the three resembles the fleur-de-lis, which, how- 

 ever, is, in the process of time, effaced by the wearing of the 

 teeth." 



Between tnree and four years the upper central incisors are 

 worn, and between four and five, the whole give indications 



