Page 176 - My FlipBook

150 * THE MICRO-ORQANISMS OF THE HUMAN MOUTH.

Notwithstanding the very considerable difficulties attending
the analysis, we notice a marked conformity between the values
found and those calculated from the atomic complex (P04)g
CaipCOg, since the latter demands Ca 38.83 per cent., PO4 55.34
per cent., CO3 5.83 per cent.
The question whether this combination has been brought to-
gether by the glue-giving substance (glutine) had to be answered
in the negative, as it also occurs in enamel which contains no
glutine.
Another question which has been broached by Hoppe-Seyler now
engages our attention : What is the relation of these salts to the
glue-giving basis-substance ? Are they precipitated in the carti-
lage according to physical laws, or are they held together by means
of the organic substance, and do they enter into a chemical union
with it ? This is a matter of importance for the understanding
of certain pathological phenomena exhibited by the teeth. As
emphasized above, the variations in the amount of salts in the
dentine are by no means great enough to explain the variations
in hardness. But in the case of a chemical union between the
organic and inorganic constituents of the tooth, we should expect
to find dentine hard or soft according as the union is firm or
unstable.
Unfortunately, our knowledge of -the nature of the combina-
tions occurring in teeth is as yet very incomplete, nor does it at
present appear how we may approach this problem experiment-
all}'. " No atfinities are known which might make a chemical
union conceivable, nor do we know any physical conditions
which could explain the impregnation of the organic substance
with this calcium phosphate carbonate."
The density of the dentine cartilage is about 0.55, consequently
about equal to that of bone ; this, by the way, shows that the
substance of the odontoblasts, as well as that of the osteoblasts,
must undergo a very great condensation during or before calcifi-
cation.
The density of the organic substance of enamel, on the other
hand, is only about 0.075. Regarded from this point, the forma-
tion of enamel is a process which essentially differs from the
formation of dentine and bone.