DEVELOPMENT OF THE ENAMEL 133 



attached to the ameloblasts, and torn away from its con- 

 nexion with the forming enamel. Both the outer and inner 

 ameloblastic membranes are well shown on Plate IV. 



Tomes is inclined to look upon these membranes as 

 non-existent, or as artificial products, but in sections which 

 have not been treated with either alcohol or acids they are 

 easily to be seen. 



The membranes appear to be dependent upon the calcify- 

 ing process, for before its commencement they are not to 



m 



f* 



FIG. 78. Macropus. Outer ameloblastic membrane (m) where amelo- 

 blasts have been detached. ( x 1,000. ) 



be seen, and the cells of the stratum intermedium are 

 mingled with the ameloblasts (figs. 75 and 77), although 

 afterwards entirely shut off from them by the outer 

 ameloblastic membrane. 



Processes from the cells of the stratum intermedium 

 apparently penetrate this membrane and communicate with 

 the ameloblasts. 



In criticizing Leon Williams's statements, C. S. Tomes says 

 that little reliance can be placed on differential staining as 

 evidence of the existence of the membranes. No doubt 

 many conditions affect these staining results, as the previous 



