Hernia, Or Rupture the protrusion of any organ outside of its natural enclosing cavity, but, in common language, limited to the escape of the abdominal viscera. Until about the 18th century this disease was neglected by the profession, and its treatment was principally in the hands of itinerant quacks; but since then it has received the attention of the most eminent surgeons of all countries. According to the seat of the protrusion, the principal kinds of hernia are : the inguinal, which comes out at the abdominal rings, following the course of the spermatic cord in the male and of the round ligament in the female respectively into the scrotum and the greater labia; the femoral or crural, passing beneath Poupart's ligament, and forming a tumor on the inner and upper part of the thigh; umbilical, in which the protrusion takes place at the navel or fetal opening of the umbilical cord; ventral, at the openings in the linea alba or lineoe semilunares; diaphragmatic, in which the abdominal organs pass into the cavity of the chest through some natural or abnormal opening in the diaphragm.

All the abdominal viscera, except the duodenum, pancreas, and kidneys, may form part of the contents of a hernial tumor; but the floating portions of the small intestines (jejunum and ileum), the omentum, and the arch of the colon, are their most frequent constituents. Hernia rarely protrudes on the posterior and lateral portions of the abdomen, which are protected by thick muscles and firm imperforated aponeuroses, and where the organs are large and but little movable; the anterior abdominal wall, on the contrary, is thin, extensible, having weak points in the inguinal rings and canals, and freely floating organs always pressing upon its yielding tissues. A hernia is said to be reducible when the protruding organ may be returned into the abdomen; irreducible when it is not thus returnable; and strangulated when, owing to its unusually close constriction, the circulation of blood in its vessels, or the natural passage of the intestinal contents, is ar-rested. The sac of a hernia is a pouch of the reflected or parietal layer of the peritoneum, which is pushed forward in proportion to the escape of the viscera; external to this are the layers of fascia?, muscles, and cellular tissue, varying in thickness according to the situation of the tumor.

When we consider the yielding nature of the abdominal walls, their liability to pressure from muscular action, and the weak points inviting protrusion of the viscera, it is not surprising that hernia is so common; it has been estimated that in the male sex at least one in five is affected by it. The exciting causes are such as suddenly or violently compress the organs by action of the abdominal muscles, such as great bodily exertion, the lifting of heavy weights, violent vomiting, coughing, and sneezing; long continued efforts in parturition, defecation, or micturition; habitual compression by corsets, belts, bandages, and heavy hip-supported clothing; falls, improper gymnastic exercises and feats of strength, severe blows and contusions. A simple hernia, easily reducible and kept so by a proper truss, is rather an annoying infirmity than a positive disease, and is often susceptible of a radical cure. - The treatment of reducible hernia is to return it to the abdomen by a process called the taxis, and to retain it in place by a properly constructed and well fitting truss. Great care is necessary in the preparation of the truss; it should fit exactly, the springs should have the right bearings and pressure, and the pads the proper shape and consistency.

Hernia may be rendered irreducible by adhesions of the sac to its contents, and of the latter to each other, or by enlargement of the contained omentum from fatty deposition; the treatment is merely palliative, except in rare and favorable cases. Strangulated hernia may be produced by a sudden protrusion through a narrow aperture after violent exertion, by swelling or spasmodic action about the neck of the sac, distention of the intestine by flatus or fasces, and swelling and congestion of the omentum and mesentery; the stricture is generally at the neck of the sac. The indications of treatment are to reduce the hernial contents by the taxis, if possible, with the assistance of relaxation of the muscles by position, by bleeding, hot baths, narcotics, tobacco enemata, cold applications, and antimonial prostration, or, in modern times, by the inhalation of sulphuric ether and chloroform; if these fail, the sac must be cautiously opened, the stricture divided by the knife, and the hernia returned. Strangulated hernia is always a dangerous affection, and frequently fatal either in itself or from the effects of inflammation. Umbilical hernia, most common in new-born children, is treated on similar principles, by the reduction of the contents, and their retention by a special bandage.

Diaphragmatic hernia, whether from congenital deficiency or accidental rupture of this partition, when strangulated, is difficult of diagnosis, and beyond the reach of operative surgery.