The tuberculous sinus is described under Tuberculosis.

A #fistula# is an abnormal canal passing from a mucous surface to the skin or to another mucous surface.  Fistulae resulting from suppuration usually occur near the natural openings of mucous canals—­for example, on the cheek, as a salivary fistula; beside the inner angle of the eye, as a lacrymal fistula; near the ear, as a mastoid fistula; or close to the anus, as a fistula-in-ano.  Intestinal fistulae are sometimes met with in the abdominal wall after strangulated hernia, operations for appendicitis, tuberculous peritonitis, and other conditions.  In the perineum, fistulae frequently complicate stricture of the urethra.

Fistulae also occur between the bladder and vagina (vesico-vaginal fistula), or between the bladder and the rectum (recto-vesical fistula).

The treatment of these various forms of fistula will be described in the sections dealing with the regions in which they occur.

Congenital fistulae, such as occur in the neck from imperfect closure of branchial clefts, or in the abdomen from unobliterated foetal ducts such as the urachus or Meckel’s diverticulum, will be described in their proper places.

CONSTITUTIONAL MANIFESTATIONS OF PYOGENIC INFECTION

We have here to consider under the terms Sapraemia, Septicaemia, and Pyaemia certain general effects of pyogenic infection, which, although their clinical manifestations may vary, are all associated with the action of the same forms of bacteria.  They may occur separately or in combination, or one may follow on and merge into another.

#Sapraemia#, or septic intoxication, is the name applied to a form of poisoning resulting from the absorption into the blood of the toxic products of pyogenic bacteria.  These products, which are of the nature of alkaloids, act immediately on their entrance into the circulation, and produce effects in direct proportion to the amount absorbed.  As the toxins are gradually eliminated from the body the symptoms abate, and if no more are introduced they disappear.  Sapraemia in these respects, therefore, is comparable to poisoning by any other form of alkaloid, such as strychnin or morphin.

Clinical Features.—­The symptoms of sapraemia seldom manifest themselves within twenty-four hours of an operation or injury, because it takes some time for the bacteria to produce a sufficient dose of their poisons.  The onset of the condition is marked by a feeling of chilliness, sometimes amounting to a rigor, and a rise of temperature to 102, 103, or 104 F., with morning remissions (Fig. 10).  The heart’s action is markedly depressed, and the pulse is soft and compressible.  The appetite is lost, the tongue dry and covered with a thin brownish-red fur, so that it has the appearance of “dried beef.”  The urine is scanty and loaded with urates.  In severe cases diarrhoea and vomiting of dark coffee-ground material are often prominent features.  Death is usually impending when the skin becomes cold and clammy, the mucous membranes livid, the pulse feeble and fluttering, the discharges involuntary, and when a low form of muttering delirium is present.