nation of the nature and affinities of extinct species, of whose organisation
the teeth are not unfrequently the sole remains.
Teeth consist of a cellular and tubular basis of animal matter
containing earthy particles, a fluid, and a vascular pulp.
In general the earth is present in such quantity as to render the
tooth harder than bone, in which case the animal basis is gelatinous,
as in other hard parts where a great proportion of earth is combined
with animal matter. In a very few instances among the vertebrate
animals, the hardening material exists in a much smaller proportion,
and the animal basis is albuminous; the teeth here agree in both
chemical and physical qualities with horn.
True teeth consist of two or more tissues, characterized by
the proportions of their earthy and animal constituents, and by the
size, form and direction of the cavities in the animal basis which
contain the earth, the fluid or the vascular pulp.
The tissue, which forms the chief part or body of the tooth,
has, hitherto, received no distinct and specific name in our
language ; a particular modification of it, which characterizes the
tusks of the elephant, is called ‘ ivory.’ Some Anatomists
have extended the application of this term to the analogous substance
in all teeth ; others have treated of it under the name of the
‘ bone of the tooth’(1) or 1 tooth-hone’; by the German Anatomists
it is termed j knochensubstanz’, ‘ zahnbein’ and ‘ zahnsubstanz ;
and some of the latest and most close-thinking writers on
dental anatomy have preferred the literal translation of one or
other of these terms to the use of the word ‘ ivory’, which
unavoidably recalls the idea of the peculiar modification of the
(1) Hunter, Natural History of the Human Teeth. Bell’s Ed. 1835, 8vo. p. 15, 16.
1 tooth-substance’ in the elephant’s tusk, to which it is restricted
in common language and in the best zoological works. (1) I propose
to call the substance which forms the main part of all teeth ‘ dentine.’(
2)
The second tissue, which is the most exterior in situation, is the
1 cement’(3).
The third tissue, which, when present, is situated between the
dentine and cement is the ‘ enamel’(4).
‘ Dentine’ consists of an organized animal basis disposed in the
form of extremely minute tubes and cells, and of earthy particles:
these particles have a two-fold arrangement, being either blended
with the animal matter of the interspaces and parietes of the tubes
and cells, or contained in a minutely and irregularly granular state
in their cavities.
The density of the dentine arises principally from the proportion
of earth in the first of these slates of combination ; the tubes and
cells contain, besides the granular earth, a colourless fluid, probably
transuded ‘ plasma’ or ‘ liquor sanguinis,’ and thus relate not only
(1) The accurate Illiger distinguishes the c substantia ossea’ of a tooth from ‘ ebur,’ and
separately defines both these modifications of the tooth substance. Prodromus Systematis Mam-
tnalium, 8vo. 1811, p. 20.
(2) Dentinum. Besides the advantage of a substantive name for an unquestionably distinct
tissue under all its modifications in the animal kingdom, the term | dentine’ may be inflected
adjectively, and the properties of this tissue be described without the necessity of periphrasis;
thus we may speak of the * dentinal’ pulp, e dentinal’ tubes or cells, as distinct from the
corresponding properties of the other constituents of a tooth. The term ‘ dental’ will retain
its ordinary sense, as relating to the entire tooth or system of teeth.
(3) Ctementum, Cortex osseus, Tenon. Crusta petrosa, Blake.
(4) Encaustum, A damns, Substantia vitrea.
a 2