Yfi^.f^^'"'^ 



part of their teeth. Red blood freely circulated through the vascular 

 dentine and the cement, and the vessels of both substances communi- 

 cated with each other by a few similar canals, which traversed the 

 hard dentine. With respect to those minute and more important tubes 

 which are the chief constituent of the unvascular dentine, and which 

 pervade the interspaces of the vascular canals in the vascular dentine 

 and cement, they form one continuous and inter-communicating system 

 of vessels, by which the colourless plasma of the blood was distributed 

 throughout the tooth for its nutrition and maintenance in a healthy 

 state. 



PRINTED BY RICHARD AND JOHN E. TAYLOR, 

 RED LION COURT, FLEET STREBI. 



