=Pernicious Malaria.=--This is a very grave form of the disease. It rarely is seen in temperate regions, but often occurs in the tropics and subtropics. It may follow an ordinary attack of chills and fever, or come on very suddenly. After a chill the hot stage appears, and the patient falls into a deep stupor or unconscious state, with flushed face, noisy breathing, and high fever (104 deg. to 105 deg. F.). Wild delirium or convulsions afflict the patient in some cases. The attack may last for six to twenty-four hours, from which the patient may recover, only to suffer another like seizure, or he may die in the first. In another form of this pernicious malaria the symptoms resemble true cholera, and is peculiar to the tropics. In this there are violent vomiting, watery diarrhea, cramps in the legs, cold hands and feet, and collapse. Sometimes the attack begins with a chill, but fever, if any, is slight, although the patient complains of great thirst and inward heat. The pulse is feeble and the breathing shallow, but the intellect remains clear. Death often occurs in this, as in the former type of pernicious malaria, yet vigorous treatment with quinine, iron, and nitre will frequently prove curative in either form. =Black Water Fever.=--Rarely in temperate climates, but frequently in the Southern United States and in the tropics, especially Africa; after a few days of fever, or after chilliness and slight fever, the urine becomes very dark, owing to blood escaping in it. This sometimes appears only periodically, and is often relieved by quinine. It is apparently a malarial fever with an added infection from another cause. =Chagres Fever.=--A severe form of malarial fever acquired on the Isthmus of Panama, apparently a hemorrhagic form of the pernicious variety, and so treated.