The suppuration is strictly localised to the part of the wound where
catgut was employed for stitches or ligatures, and shows little tendency
to spread. The infected part, however, is often long of healing. The
irritation in these cases is probably due to toxins in the catgut and
not to bacteria.

When suppuration occurs in connection with buried sutures of
unabsorbable materials, such as silk, silkworm gut, or silver wire, it
is apt to persist till the foreign material is cast off or removed.

Suppuration may occur in the track of a skin stitch, producing a _stitch
abscess_. The infection may arise from the material used, especially
catgut or silk, or, more frequently perhaps, from the growth of
staphylococcus albus from the skin of the patient when this has been
imperfectly disinfected. The formation of pus under these conditions may
not be attended with any of the usual signs of suppuration, and beyond
some induration around the wound and a slight tenderness on pressure
there may be nothing to suggest the presence of an abscess.

_Acute Suppuration of a Mucous Membrane._--When pyogenic organisms gain
access to a mucous membrane, such as that of the bladder, urethra, or
middle ear, the usual phenomena of acute inflammation and suppuration
ensue, followed by the discharge of pus on the free surface. It would
appear that the most marked changes take place in the submucous tissue,
causing the covering epithelium in places to die and leave small
superficial ulcers, for example in gonorrhœal urethritis, the
cicatricial contraction of the scar subsequently leading to the
formation of stricture. When mucous glands are present in the membrane,
the pus is mixed with mucus--_muco-pus_.