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100 THE MICRO-OROANISMS OF THE HUMAN MOUTH. ;
to be caused bv the aeeumulation of calcareous remains of
vibrios ; Klebs, GaHppe, and others express the opinion that
tartar is to be regarded as an excretion of micro-organisms. ^
There is such a vast difference between tartar and coral, as
well as between bacteria and coral-forming polyps, that Le-
beaume's comparison is certainly unwarranted, while the theory
of Klebs is an apparent contradiction of facts known to every
practitioner. As is well known, tartar is formed chiefly, some-
times exclusively, where the salivary glands discharge their pro-
ducts into the oral cavity, particularly on the lingual surfaces of
the lower incisors. In no other locality of the mouth have the
bacteria so little opportunity of gaining a foothold as at this par-
ticular point, since the tongue keeps these surfaces nearly free
from bacteria and soft deposits.
^Moreover, the amount of tartar in a given mouth is in no wise
proportional to the nund:)er of l)acteria contained in the same, nor
am I aware that calcareous deposits anyway resembling tartar
have l)een observed in pure cultures of mouth-bacteria.
Othir considerations also seem to me to render this explana-
tion untenalde. Tartar contains about 25 per cent, of organic
matter and 75 per cent, of salts (almost exclusively lime-salts
bacteria, on the other hand, contain about 0.5 per cent, of
ashes, consequently the percentage of ashes in bacteria is equal
to but y|-g- of that in tartar; a formation of tartar, therefore, by
an accumulation of the calcareous remains of bacteria appears
to me to be out of the question.
Xormal saliva contains calcium phosphate as well as carbon-
ate ; these are held in solution in the l)lood and in the glands by
carbonic acid. When the saliva enters into the mouth, the
carbonic acid escapes and the lime-salts are precipitated. The
following experiment will demonstrate this process
Small quantities of calcium phosphate and calcium carl)onate
are brought into water charged \a ith carbonic acid (a bottle of
soda-water serves the purpose very well), shaken at brief inter-
vals, and left standing until the water becomes quite clear. On
opening the bottle very carefully and permitting the carbonic
acid slowl}^ to escape, the precipitation of the salts held in solu-
tion will produce a distinct cloudiness.
100 THE MICRO-OROANISMS OF THE HUMAN MOUTH. ;
to be caused bv the aeeumulation of calcareous remains of
vibrios ; Klebs, GaHppe, and others express the opinion that
tartar is to be regarded as an excretion of micro-organisms. ^
There is such a vast difference between tartar and coral, as
well as between bacteria and coral-forming polyps, that Le-
beaume's comparison is certainly unwarranted, while the theory
of Klebs is an apparent contradiction of facts known to every
practitioner. As is well known, tartar is formed chiefly, some-
times exclusively, where the salivary glands discharge their pro-
ducts into the oral cavity, particularly on the lingual surfaces of
the lower incisors. In no other locality of the mouth have the
bacteria so little opportunity of gaining a foothold as at this par-
ticular point, since the tongue keeps these surfaces nearly free
from bacteria and soft deposits.
^Moreover, the amount of tartar in a given mouth is in no wise
proportional to the nund:)er of l)acteria contained in the same, nor
am I aware that calcareous deposits anyway resembling tartar
have l)een observed in pure cultures of mouth-bacteria.
Othir considerations also seem to me to render this explana-
tion untenalde. Tartar contains about 25 per cent, of organic
matter and 75 per cent, of salts (almost exclusively lime-salts
bacteria, on the other hand, contain about 0.5 per cent, of
ashes, consequently the percentage of ashes in bacteria is equal
to but y|-g- of that in tartar; a formation of tartar, therefore, by
an accumulation of the calcareous remains of bacteria appears
to me to be out of the question.
Xormal saliva contains calcium phosphate as well as carbon-
ate ; these are held in solution in the l)lood and in the glands by
carbonic acid. When the saliva enters into the mouth, the
carbonic acid escapes and the lime-salts are precipitated. The
following experiment will demonstrate this process
Small quantities of calcium phosphate and calcium carl)onate
are brought into water charged \a ith carbonic acid (a bottle of
soda-water serves the purpose very well), shaken at brief inter-
vals, and left standing until the water becomes quite clear. On
opening the bottle very carefully and permitting the carbonic
acid slowl}^ to escape, the precipitation of the salts held in solu-
tion will produce a distinct cloudiness.
