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THE ENAMEL ORGAN. 69

porary enamel organ becomes separated from its cord. Between the
temporary enamel organ and the permanent enamel bud, the cord
of the temporary enamel organ is seen to be breaking up and losing
its connection with the stratum Malpighii ; while the cord for the per-
FiG. 52.

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Section of developing tooth, embryo of calf i,x liJ^W) : a,b, nuclei of reticulum of enamel organ,
showing spongiose character ; c, outer ameloblastic membrane ; d, inner ameloblastic mem-
brane; e,/, enamel globules faintly showing nuclear network. (Dr. J. Leon Williams' speci-
men.)
manent tooth appears as a continuation of the Malpigliian end. The
cord for the permanent incisor in the human embryo is formed about the
lifth month, and while descending into the embryonic connective tissue
assumes a spiral form of growth, as do the necks of most of the enamel
organs of the permanent teeth, growing down to take their positions
under the tem]iorary teeth, where they go through all the changes that