in physic, the communicating a disease from one body to another. In some diseases it is only effected by an immediate contact or touch, as the venom of the pox; in others it is conveyed by infected clothes, as the itch; and in others it is supposed to be transmitted through the air at a considerable distance, by means of fleams or effluvia exsiring from the sick, as in the plague and other pestilential disorders, in which case the air is said to be contagious, though this has been disputed.