THE DEVELOPMENT OF THE TEETH. 



139 



which they penetrate into the surrounding parts, and other 

 such characteristics exist not only between the germs of teeth 

 of different animals, but even between those of teeth situated 

 in different parts of the mouth of the same animal, so that 

 but little importance is to be attached to them. 



DENTINE ORGAN. 



The dentine germ, or dentine bulb, of which the origin 

 has been already described, at first was nothing more than 



FIG. 63 ('). 



a part of the subuiucous tissue of the jaw which had become 

 more rich in vessels and cells than other neighbouring parts, 



( l ) Tooth sac of a calf. a. Tootli sac. a 1 a 2 . Its outer and middle 

 portions, b. Stellate cells of enamel organ, c. External epithelium of 

 enamel organ, d. Internal epithelium of enamel organ, e. Odontoblasts. 

 /. Dentine bulb in papilla, g. Vessels in dentine bulb. i. Points where 

 the sac becomes fused with the base of the dentine papilla. 



