AGRICULTURAL 

 LIBRARY, 



VE TE1UNA /,' ) ' DI-.\ TA L S UKdk /,' ; '. 47 



gradual reduction in the volume of the -out, 

 is in an exact relation to the advance of the crown of 

 the permanent tooth, so that at the time when the de- 

 ciduous tooth is ready to be extruded from the jaw, 

 the crown of the permanent tooth which is to suc- 

 ceed it is often visible in the depression left after 

 extraction of the remains of the milk tooth. 



" The manner in which the absorption of the root 

 of the milk tooth is accomplished has been the sub- 

 ject of careful study, and many theories have been 

 advanced to explain this singular phenomenon. The 

 most celebrated investigators in the domain of dental 

 science have given the subject much attention. 

 Czermak, Bodeker, Tomes and more recently 

 Abbott have made valuable contributions to the 

 solution of the question, which, however, cannot yet 

 be said to be absolutely settled. All observers unite 

 in describing the gradual excavation or corrugation 

 of the hard textures of the root of the tooth, very 

 similar to the appearances noticed in the absorption 

 of portions of ivory, surgical cat-gut, silk, etc., when 

 brought into relation with the textures of the living 

 and healthy organism. The substance of these 

 materials is invaded by numerous cavities, in which 

 a softened and jelly-like content is found, and which 

 penetrates further and further into the textures of 

 the tissue. The advance of the process of soften- 

 ing is followed by continuous absorption of the dis- 



