Epidemic Disease and Quarantine

There are two grand divisions under which all contagious diseases may be classed: -- 1. Those which spring from organized living beings, and from the life in them, and which enter, as it were, into the life of those in whom they reproduce themselves -- such as small-pox and measles. These become so domesticated with the habit and system, that they are rarely received twice. 2. Those which spring from dead organized, or unorganized matter, and which may be comprehended under the wide term _malaria_.

You may have passed a stagnant pond a hundred times without injury: you happen to pass it again, in low spirits and chilled, precisely at the moment of the explosion of the gas: the malaria strikes on the cutaneous or veno-glandular system, and drives the blood from the surface; the shivering fit comes on, till the musculo-arterial irritability re-acts, and then the hot fit succeeds; and, unless bark or arsenic -- particularly bark, because it is a bitter as well as a tonic -- be applied to strengthen the veno- glandular, and to moderate the musculo-arterial, system, a man may have the ague for thirty years together.