60 MICROSCOPIC ANATOMY OF THE TEETH 



Form and Within recent years some researches on the form and 

 arrangement of the enamel prisms in human and some other 

 mammalian enamels have been published by E. Smreker 

 (16) and Professor von Ebner (6 a). Smreker, who was the 

 first to point out this form of modification of the enamel 

 prism, asserted that the majority of the prisms in human 

 enamel are not rounded or polygonal in transverse section, 

 but have an arched form, owing to the prisms being longitu- 



FIG. 22. Marsupial enamel. Teased preparation showing calcospherites 

 in the laminse. (x 1,000.) 



dinally grooved and fitting into one another. Von Ebner 

 confirms these observations in his paper published in the 

 same year (1905). Smreker compares the arrangement of 

 the prisms to that of the cells of the prickle cell layer of 

 a pavement epithelium. In the epithelium the cells are seen 

 to present convex and concave margins, the concavity being 

 dependent upon the convexity of the cell beneath (fig. 23). 

 Where one cell comes into contact with a single neighbouring 

 cell there is a single concavity, but if two or more cells are 

 in contact with a single cell the single cell will show two or 

 more concavities. Comparing the transverse section of the 



