DEFINING THE BLASTEMA. 35 



small quantity of the condensed blastema in the 

 minute interspaces left between the cells, which are 

 pressed together into hexagonal or polygonal forms. 

 * * * The field of the final metamorphosis of the 

 cells into the molds for the reception of the solidifying 

 salts is confined to close contiguity with the surface of 

 the dentinal-pulp. Here the cells increase in length, 

 lose all trace of their nucleus, and become converted 

 into long and slender cylinders, usually pointed at both 

 ends, and pressed by mutual contact into a prismatic 

 form. These cylinders -have the property of imbibing 

 the calcareous salts of the enamel from the plasmatic 

 fluid, and of compacting them in a clear and almost 

 crystalline state m their interior. * * 



"The blastema or fundamental tissue of the capsule 

 is, at first, semitransparent and of a pearly or opaline 

 color, but is soon richly ornamented by the plexiform 

 distribution of the blood-vessels. As the period of its 

 calcification approaches, which is later than that of 

 the dentinal-pulp, it becomes denser, and exhibits nu- 

 merous nucleated cells. The blastema itself presents 

 more evidently a fine cellular or granular structure, in 

 which the calcareous salts are impacted in a compara- 

 tively clear state, constituting the framework of the 

 cemental tissue. The characteristic features of this 

 tissue are due to the action of the proper nucleated 

 cells upon the salts of the plasma diffused through the 

 blastema in which those cells are imbedded, the cells 

 being characterized by a single, large, granular nu- 

 cleus, which almost fills the clear area of the cell itself. 

 If, when the formation of the cement has begun in the 

 incisor or molar of a colt, one of the detached specks 

 of that substance, with the surrounding and adhering 

 part of the inner surface of the capsule in which it is 



