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136 HUNTER ON THE TEETH.
subservient to its formation, much in the same manner as the
Pulp is to the body of the Tooth.
From its situation, and from the manner in which the Teeth
grow, one would imagine that the Enamel is first formed ; but
the bony part begins first, and very soon after the Enamel is
formed upon it. There is another pulpy substance opposite to
that which we have described, (j) it adheres to the inside of the

(J) We have seen (note g) that Hunter has already alluded to the
so-called organ of the enamel ; he here describes it minutely. There
is a great difference of opinion amongst writers upon the subject of the
formation of the enamel, and on the function of the so-called enamel
organ.
Kolliker describes the enamel organ, organon adamantince, as embrac-
ing with its inner concave surface the tooth pulp in its entire extent
and as being connected at its outer side with the tooth sac, but in such
a manner that it possesses a very small free border at the base of the
tooth germ. Its principal mass consists of anastomosing stellate cells,
or reticulated connective tissue, enclosing in its interspaces a large
quantity of albuminous fluid. " This gelatinous areolar tissue is
thickest immediately before the commencement, and in the first stages
of ossification. Thus, in the fifth and sixth months, it is ^ to f of a
Vienna line in the newly-born infant, on the other hand,
; only
0-16'' to 0-2". At this period it also possesses vessels in its outer third,
and its network has become metamorphosed into true connective tissue.
Upon the inner side of the spongy tissue of the enamel organ, there is
situated the so-called enamel membrane, membrana adamantina (Rasch-
kow) a genuine cylinder epithelium, with cells which measure 0"012'" in
length, 0-002'" in breadth, are finely granular and delicate, and contain
elongated, round nuclei, often situated at the apices of the cells."
Schwann, and most other authors, have assumed that the enamel
fibres are nothing else than the ossified cells of the enamel membranes.
Professor Huxley, on the contrary, asserts that this is impossible,
because the enamel in all stages of its development is covered by the
membrana praeformativa of the dental pulp, and is separated from it by
the enamel membrane. Therefore he asserts that the enamel is formed
independently of the enamel membrane, and beneath the membrana
praeformativa, which afterwards is converted into the cuticle of the
enamel, or Nasmyth's membrane. Huxley's observations have been
repeated, and to a great extent confirmed, by Lent, who finds that un-
doubtedly a delicate structureless membrane may at all times be sepa-
rated from the surface of the developing enamel when treated with
dilute acids, and that this membrane, whilst the dentine is not fully