Page 205 - My FlipBook

MICROSCOPICAL PHENOMENA OF DECA V 179

see a very distinct line of pickets. This is followed by an interval
which in the language of bacteria might be put down at several
furlongs, since it is about one thousand times the length of an aver-
age-sized bacillus. Then comes the vanguard, and finally, after
another interval, the main body of the invading hordes. I was
not able to find any cause for this peculiar disposition of the forces.

A question which has often l)een mooted now arises : Can the
bacteria })enetrate into normal dentine ? This question must be
answered in the afiirmative. Since the average diameter of the
dentinal tubules is greater than that of the bacteria found in the
is but reasonal;)le to conclude, a priori^ that bacteria
mouth, it
may under certain circumstances make their way into the tu-
bules of apparently intact tissue. Under high power we also
often oljserve that a small number of bacteria, outposts, as it
Fig. 74.
Fig. 73.

^^^'^

mmw

Micrococci pexetratixg the C.\xai.s
OF Solid Dentine, in a partially absorbed
and abscessed but not decayed root. 700 : 1.
LoN(iiruDi.\AL Section
OF Decayed Dentine.
were, have penetrated into the nor-
showing caverns, or foci
mal dentine without, however, pro- of liquefaction, filled with
bacteria. 150 : 1.
ducing any visible changes.
We notice also in partly resorbed, abscessed roots, particularly
of milk-teeth (Fig. 73), that bacteria work themselves into the
open ends of exposed tubules for a short distance. The great
mass of bacteria, however, in decay of the dentine does not
even penetrate up to the normal dentine, much less into it.
From this it is evident that the proposition which I estalilished in