TACT resembles a lubricating oil, by virtue of which needful contact is guarded against degenerating into sore rubs and grazes.
According to the ancient Oriental practice of leechcraft, oil was called in to heal physical wounds.
Hear a story in point:--
The pleasure-grounds of a certain Bishop contained an apparatus for turning on and off artificial waters. One day in honor of guests, the Bishop issued orders to his servants to work the fountains: but finding that this had caused offence, on the next similar occasion he gave leave to his servants to play the fountains. Whereupon all went smoothly.