INTRODUCTION. Ivii 



in striking degrees, those changes of the contained matter to 

 which I have elsewhere suggested that their own multiplication 

 might be due. In the present situation and condition it is obvious 

 that such changes must be preparatory, either to their disappearance 

 and removal, or to some important share which they are destined 

 to take in the development of the dental tissue. The stagnant 

 corpuscles nearest the vascular and unchanged pulp presented the 

 irregularity of contour, which has given rise to the term ' mulberry,' 

 or ' granulated' applied to such altered blood-discs, when seen in 

 other circumstances. These corpuscles in other respects, as colour, 

 size, and general form, retained their usual character. The blood- 

 discs nearer the cap of dentine exhibited more plainly the contained 

 granules, to the commencing development of which the irregular 

 contour above-mentioned is due : this appearance was associated 

 with an increase of size, a change from the circular to the elliptical 

 form, and a gradual loss of the characteristic colour, which was 

 longest retained by the central granular matter. The tunics of the 

 capillary vessel containing the above aggregated and altered blood- 

 discs become gradually attenuated, and disappear, as if dissolved, 

 before reaching the field of conversion. I once inclined to the 

 belief that these modified blood-discs afforded fresh cell-material 

 to supply the space left by the retreat of the circulating currents. 



The open mouths 'of the central last-formed ends of the 

 calcified dentinal tubes are always ready to receive the plasma 

 transuded from the capillaries remaining in the uncalcified part 

 of the pulp or in those tracts of it which constitute the vascular 

 canals. 



The enamel pulp differs from the dentinal pulp at its first 

 formation by the more fluid state of its blastema and by the fewer 

 and more minute cells which it contains. (PI. 1, fig. 4, h.) The 



e 



