ON ABSORPTION. 27 



sheep, the second premolar (the first being per- 

 manently absent) is represented by no deciduous 

 organ; but appears to be developed by a gemmi- 

 parous process from the next posterior, analogous 

 to the development of the second and third molars 

 in mammals generally. Constant with my own 

 experience, absorption takes place on the fang of the 

 deciduous tooth at the neck, corresponding to the 

 connecting link between the two undeveloped teeth. 

 (Plate III., Figs. 1 and 2.) 



In reviewing these several cases of absorption, we 

 perceive that the action may be set up through the 

 means of widely difierent causes. Abnormal absorp- 

 tion may result from some extreme injury or disease. 

 Normal absorption may take place at either ex- 

 tremity of the growing tooth, should it be brought 

 into contact with a deciduous tooth. 



There may be, moreover, an amalgamation of the 

 two, in consequence of the organ being attacked by 

 disease during the process of absorption, as seen in 

 Plate III. Figs. 3 and 4. If we give our atten- 

 tion to those conditions that are constant under 

 every kind of absorption, we shall perceive first, that 

 the peridental membrane which protects the fang of 

 the tooth is destroyed at those points where absorption 

 is in progress, and next, that it must be in immediate 

 contact with a highly vascular tissue. It matters 

 not whether the capillary plexus be the result of 

 disease or a constant law in nature. The process is 

 the same. It is the inducing cause alone that differs. 



