Authorities do not even agree as to the sequence of the forms of the disease, if there be such sequence.

Some assert that the white form is the early stage and that the disease may never progress beyond it; others assert that the white spots are merely the permanent scars, left after the disappearance of the disease itself.

Maps of distribution seem to show a distinct relation of the disease to altitude and character of water-supply.

The common herd attribute it to an insect sting, to drinking of certain water, or to bathing in certain pools.

Usually, there is no pain or danger connected with the trouble, except in the red form, but if the person affected changes residence, itching and some discomfort may temporarily ensue.