I ordain flebotomy, and on the instant." "Flebotomy! that is bloodletting: humph! Well, no matter, if 'tis sure to cure me, for I will not lie idle here." The doctor let him know that flebotomy was infallible, especially in this case.
"Hans, go fetch the things needful, and I will entertain the patient meantime with reasons." The man of art then explained to Gerard that in disease the blood becomes hot and distempered and more or less poisonous; but a portion of this unhealthy liquid removed, Nature is fain to create a purer fluid to fill its place.

Bleeding, therefore, being both a cooler and a purifier, was a specific in all diseases, for all diseases were febrile, whatever empirics might say.
"But think not," said he warmly, "that it suffices to bleed; any paltry barber can open a vein (though not all can close it again).

The art is to know what vein to empty for what disease.

T'other day they brought me one tormented with earache.

I let him blood in the right thigh, and away flew his earache.