Page 928 - My FlipBook

938 DISEASES OF THE PERIDENTAL MEMBRANE. ;

Among these burrowiiigs of pus in this class of abscesses some gen-
eral rules may be pointed out, and some particular forms that occur
oftener than others may be mentioned. It is a general law of the bur-
rowing of pus that it will go in the direction of the least resistance
Fig. 493.

Fig. 494.

Chronic Alveolar Abscess at the Root of a Chronic Alveolar Abscess at the Root of an Upper
Lower IncLsor: ", abscess-cavity in the Incisor with P'istula discharging on the (lum:
bone; 6, fistula discharging on the gum; a, abscess-cavity in the bone ; b, mouth of
c, lip; this law pertains more especially to the acute forms of abscess. In the-
chronic forms, in which the movement of the pus is very gradual, it is
guided largely by gravitation, and therefore sinks to a lower point.
Now, these two forces, acting together, will explain most of the move-
ments of })us in the burrowings of chronic abscess. If, in the down-
ward wanderings of the pus, it comes in contact with a more dense
tissue, it will usually be deflected from its course toward that of less
resistance ; or if it be entangled in the fibres of such a tissue as the
muscular and these run at an angle with the perpendicular, there will
be seen a tendency to follow instead of to cross the fibres. Again, if
the pus is burrowing in a softer tissue and in its course comes in con-
tact with a muscle, it will usually be deflected and pass around the more
den.se tissue in the direction most favored by gravitation. In the same
way, it will be turned from its course by dense fascia and burrow
beneath it. This is the general law observed in studying the burrow-
ings of pus in cases of chronic abscess, but it is by no means univer-
sal, for cases are occasionally presented in which it seems to be
directly disobeyed. In the nutss of cases, however, these will be found
to be exceptional.
Now, by the ajijilication of the.se laws we will be assisted in tracing
a discharge to its source, though in some exceptional cases it may mis-