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60 EMBRYOLOGY OF THE DENTAL TISSUES.
shape somewhat like a bud, and this is the first indication that a tooth
is to be developed—the commencing growth of" the enamel organ.
This ingrowth increases, and assumes the sha])e of a tubular gland,
pushing its way into the connective tissue. It may now be called an
EPITHELIAL CORD, and at the end farthest from the epithelium proper
a growth of cells takes place, this part ex))anding from the multi])lica-
tion of cells within, which causes it to assume the form of a Florentine
flask.
Just at this time, at a point somewhere between this ex])anding ])art
and the Malpighian layer above, a budding takes place from this cord,
which is the commencing growth of the enamel orrjan of the permanent
tooth. A change is taking pkice in the embryonic tissue just under the
flask-shaped enamel organ ; a very active growth of cells is seen to be

Via 41,

Section of jaw, embryo of pis, showing growth of enamel organ and deutiii germ : 1, enamel
organ ; 2, dentin germ ; 3, growth of jaw ; 4, tongue.

going on, and this activity results in the formation of a pa])iUa, the first
stage in the growth of the dentin germ.
As the enamel organ enlarges by an increase of cells within it, the
borders of its base grow inw^ard, covering the dentinal papilla like a
cap or hood, enclosing it at its base. The cells within the enamel
organ are seen to have changed ; they are no longer like epithelial