34 TOOTH-GERMS. 



idly increase by successive additions of nucleated cells, 

 apparently derived from material supplied by the cap- 

 illary plexus at the base. The capillaries now begin 

 to penetrate the substance of the pulp itself, where 

 they present a subparallel or slightly diverging pencil- 

 late arrangement, but preserve their looped and retic- 

 ulate termination near the apex of the pulp. Fine 

 branches of nerves accompany the capillaries, and ter- 

 minate also in loops. * * * The primary cells and 

 the capillary vessels and nerves are imbedded in and 

 supported by a homogeneous, minutely subgranular, 

 mucilaginous substance, the ' blastema.' * * * The 

 v-ascularity of the dentinal-pulp, and especially the 

 rich network of looped capillaries that adorns the 

 formative peripheral layer at the period of its func- 

 tional activity, have attracted general notice, and have 

 been described by Hunter and subsequent authors. By 

 most this phenomenon has been regarded as evidence 

 of the secreting function of the surface of the pulp, 

 and the dentine as an outpouring from that vascular 

 surface which was supposed to shrink or withdraw 

 from the matter excreted. * * * 



" The enamel-pulp differs from the dentinal-pulp at 

 its first formation by the more fluid state of its blas- 

 tema, and by the fewer and more minute cells which 

 it contains. The source of this fluid blastema appears 

 to be the free inner vascular surface of the capsule. 

 As it approaches the dentinal-pulp the blastema ac- 

 quires more consistence by an increased number of its 

 granules, and it contains more numerous and larger 

 cells. Many of these show a nuclear spot, others a 

 nucleus and nucleolus. The spherical nucleolar cells 

 in the part of the blastema further from the capsule 

 are so numerous as to form an aggregate mass, with a 



