The hydatid cyst is usually single, the daughter-cysts being in the cavity of the mother-cyst, which may be of enormous size, filling the abdomen and pushing the diaphragm high into the thorax. The tiver-tissue is atrophied in proportion to the size of the cyst; that is, the pressure to which it is subjected. The parasite may die. Then the fluid becomes ab I sorbed, the capsule shrivels, and within I its remains are found fat-drops, choles terin crystals, and hooklets. The capsule I may become inflamed and an abscess re ! sult.
In lower animals the cyst may be multiple, the daughter-cysts developing outward from the mother-cyst: exoge no-us.
A third form is multilocular. In this the daughter-cysts are surrounded by fibrous tissue and all become consolidated , into a multilocular mass resembling a I colloid cancer, for which it was formerly I mistaken.
Prognosis.—Hydatid cyst of the liver is a serious disease, proving fatal in I about 25 per cent. of the cases. The course of the disease is chronic, some times lasting as long as thirty years. Re covery may follow death of the cchino coccus, which occurs occasionally, pos sibly from escape of bile or blood into the cyst. As a rule, the cyst ruptures on account of its continued increase in size. The rupture may take place into the peritoneal cavity and is usually fatal from shock; the fluid, being sterile, does not cause peritonitis. If inflammatory adhesions to the colon, stomach, small intestine, or right kidney have preceded the rupture, the cyst may rupture into one of these organs, with discharge of the fluid by vomiting, diarrhcea, or with the urine. If the cyst is situated in the dome of the liver it may rupture into the pleura or pericardium. The latter is fatal, but recovery may follow discharge through a bronchus. Rupture may occur into the hepatic vein, or the vena cava and cause sudden death. The cyst may open into the bile-passages and recov ery follow, although grave symptoms usually result from obstruction and sec ondary infection.
The most favorable result is by ad hesion to the abdominal wall and per foration externally, usually near the umbilicus. Tbe cyst frequently sup purates, pyogenic organisms gaining ac cess to the cavity by tbe blood or bile, or from a neighboring inflammatory focus. As in abscess, the pus here also is said to be usually sterile.
Treatment. — Operation alone offers hope of relief, and brilliant results have followed such intervention. The simplest
operation consists in aspiration, and is frequently successful. If not successful, injection of antiseptic fluid should be resorted to. Various antiseptics have been recommended, the last of which is probably silver-nitrate solution (1 to 500). It is said to act by precipitating the chlorides and leading. to the death of the parasite.
Statistics of abdominal section for hy timid of the liver show extremely favor able results.-6S eases, with 7 deaths,— ithin a fraction of 90 per cent. of re coveries. The method of operation by t\%o stages, producing peritoneal adhesion by incision and packing with carbolized gauze, shoNNed a mortality of a fraction over 10 per cent.; the operation by caus tics gave a mortality of 33.6S per cent., while that by canal(' a dente/ire was 26.66 per cent. Thoracic incisions for hydatids of the liver occupying the convexity of the ornn show a high rate of mortality. 'Where an hydatid cyst of the liver bas ruptured into the pleura, free incision into the pleural cavity appears to be the only treatment which holds out a fair promise of success. Thomas (Brit. Med. Jour., Sept. 28, 'S9).
Aspiration performed only in cases of simple cysts of the liver without daugh ter-progeny, and in those that have not suppurated. Reference made to Davies Thomas's statistics,-411 tapping-opera tions on liver-cysts: 73 died, 5 not re lieved, 92 failed to cure, 6S relieved, 163 reputed cured, and 10 cases result un known. Alexander H. Ferguson (An nual, '94).
Method of Baccelli, which consists of injection into the cyst of 20 cubic centi metres of distilled water containing 0.02 gramme of corrosive sublimate after the withdrawal of 30 cubic centimetres of the liquid, should be practiced in the treat ment of echinococeic cysts before a for mal operation is undertaken. Stefanile (Inform Med., No. 76, '96).
The true surgical treatment of hy datid cysts of the liver consists in direct incision made by the anterior abdominal route, by the transpleural route, or by the lumbar incision. Median or lateral laparotomy should be reserved for antero inferior or antero-superior cysts. The transpleural route with resection of the ribs is the best way of reaching sub diaphragmatic cysts which are deeply placed. Lumbar incision allows the sur geon to reach cysts in the posterior and lower part of the liver. Bolognesi (Bull. GC-n. de Th6r., Mar. 30, '96).