ANIMAL DENTISTRY. 21 



Fats .58 



Cartilage 20.42 



Soluble salts i. 



Microscopically it reveals a homogeneous substance per- 

 forated throughout with small canals (the dentinal tubules) 

 which anastomose freely with each other and extend out- 

 ward from the pulp cavity to the surface where they termi- 

 nate in large lacunae (the spaces of Czermak), which in 

 turn communicate with the. canaliculi of the crusta petrosa 

 at the fang, and cuticle of the enamel at the crown. The 

 tubules are from four to five microns in diameter at the pulp 

 cavity, and one to two microns at the surface of the dentine. 



ENAMEL. 



The enamel is the hardest of the dental tissues contain- 

 ing more than 96 per cent of inorganic matter. It is ar- 

 ranged upon the dentine in the form of a thin cap over the 

 crown and extending beyond the alveolar margin over a 

 part of the fang. In the herbivorous animals it is deeply 



Fig. 3. 

 Enamel (Magnified). 



Fig. 4. 



The Enamel Organ Dissected from 



the First Molar of a Small 



Ruminant. 



folded into the table to form the well known depression 

 characteristic of these teeth, the infundibulum. In the virgin 

 tooth it covers the entire table surface, but soon wears of? at 

 that point from the mastication of food, leaving only its 

 edges projecting at the grinding surface. In the incisor 

 teeth it is the outer covering of both the labial and lingual 

 surfaces, throughout the life of the animal, but in the molars 



