650 THE TEETH. 



whether the ivory "be simply a product of the pulp, or a transformation of its 

 substance." " The formative surface of the pulp displays a regular cellular 

 arrangement. The radiating rows of cells are surrounded by a well-defined 

 scalloped border, from which occasionally processes are observed to project 

 at regular intervals." This author also describes and illustrates several eases 

 of ossification of the pulp. 



Kolliker * noticed new formations of dentine and cement on the walls of 

 the pulp-cavities of teeth. 



L. S. Bealet maintains as follows: " The tissue of the pulp, it must be 

 distinctly borne in mind, is not converted into dentine ; neither does dentine, 

 nor the tissue from which it is formed, exhibit any characters which justify us 

 classifying it with the connective tissues. I agree with Kolliker that the den- 

 tinal cells are the only active agents concerned in the formation of dentine, 

 but cannot regard the canals as direct processes of the whole dentinal cells, nor 

 admit that the matrix is an intercellular substance." " The mass of the pulp 

 is composed of a simple form of connective tissue, with numerous oval and 

 triangular corpuscles (germinal matter) not unlike that of which the mucous 

 tissue of the umbilical cord consists." 



E. J. Hulme \ gives a good description of the new formations in the pulp- 

 cavity. He names four varieties, viz. : secondary dentine, dentine of repair, 

 osteo-dentine, and nodular dentine, but he is of the opinion that the term 

 secondary dentine would suffice for all varieties. 



R. Hohl says that new formations of dentine are found within the soft 

 tissue of the pulp as well as on its periphery in connection with the pri- 

 mary dentine. The microscopical structure of these formations presents the 

 following deviations from normal dentine : the canaliculi run in all directions ; 

 now and then they enlarge like a sac, or terminate in large holes, which, how- 

 ever, ought not to be regarded as bone-corpuscles. Osteo-odontomes are 

 mixed formations, and show dentine in one and cement in another place. 

 Osteomata are found both free and adhering to the walls of the pulp-cavity. 

 The contents of the bone-cells, he believes, is a clear liquid, although in some 

 places it looks granular. 



Franz Boll || maintains as follows: "An examination of a specimen of 

 pulp-tissue by 500 diameters will exhibit, besides the numerous medullated 

 nerve-fibers, a large quantity of peculiar, silk-like, shining fibrillse, which 

 prove to be non-medullated nerve-fibers. The transition of medullated 

 into non-medullated nerve-fibers goes on quite gradually ; the latter at first 

 exhibit alternate expansions and constrictions in their diameters ; soon they 

 appear as naked, homogeneous axis-cylinders. The peripheral portion of 

 the pulp is composed of a continuous layer of elongated cells, which, by long 

 processes extending into the dentinal canaliculi, adhere to the dentine. If 

 this film adhering to the wall of the pulp-chamber is carefully scraped off 

 and brought under the microscope, we observe that it, besides the peripheral 

 cells, contains some portions of the pulp-tissue. In these we notice a large 

 number of non-medullated nerve-fibers, after teasing the specimen with fine 

 needles. Some of these course between the peripheral cells. Although I 



* " Gewebelehre," iv., Aufl. t " On the Structure and Growth of the Tissues," 1865. 



* "On Calcification of the Dental Pulp." Transactions of the College of Dentists of 

 England, 1861. 



3 " Ueber Neubildungen derZahnpulpe." Halle, 1868. 

 || "Archiv. f. Mikroskop. Anatomic," vol. iv., 1868. 



