CLEARNESS OF THE ENAMEL- FIBERS. 135 



cracks or fissures extending into the enamel. The 

 fibers are rather more wavy in the thicker enamel of 

 the molar teeth (Plate 137, b). 



"If the enamel is viewed in sufficiently thin sec- 

 tions it is free from those wavy, dusky markings which 

 are produced by the more tortuous fibers of the human 

 enamel; and I have been unable to distinguish any 

 transverse striae in the fine fibers of that tissue in the 

 horse. The appearance of such is given by thicker 

 sections of the enamel-fibers taken obliquely across 

 them, and is produced by the cut ends of the fibers." 



