26 ON ABSORPTION. 



the typical number of teeth — viz., forty-four — 

 the young organs lodge in their own alveoli, and pos- 

 sess plenty of room for development : they encroach 

 not upon the alveoli of the previously existing set. 

 The consequence is, as distinctly illustrated in the 

 annexed sketch (Fig. 6, Plate II.), that the deci- 

 duous fangs remain entire, although the perma- 

 nent teeth are nearly complete in their develop- 

 ment. 



Moreover, it is not uncommon to meet in practice 

 with deciduous teeth that retain their position in 

 the mouth and fulfil the duties of permanent 

 teeth. This may be the result of an arrest of de- 

 velopment in the permanent organ, or from some 

 abnormal condition forcing the permanent tooth 

 out of the regular arc, as exhibited in the accom- 

 panying drawing of a fossil rhinoceros (Plate I). 



The teeth retained can only be so by means of 

 deeply-seated unabsorbed fangs — an opinion which 

 has been corroborated by those which circum- 

 stances have required us to remove. 



Opposed to this, we find absorption in progress 

 under very distinct conditions. We have observed 

 in the pig, where the development of the huge 

 canine tusk has encroached upon the alveolus of the 

 first deciduous molar (Fig. 6, Plate II.), that it had 

 induced absorption of the extremity of the fang of 

 that tooth. In this case the process was carried 

 on at that extremity of the new tooth, and during 

 the time that it wag developing dentine. In the 



