Note:  Do not rely on this information. It is very old.

Tapping_

Tapping_ The removal of collections of fluid from the cavities of the pleura or peritoneum, or from cysts, hydroceles, abscess cavities, etc., is effected by the operation of tapping. This operation is usually performed with a trocar and cannula [CANNULA], sometimes in cunjunction with some form of apparatus known as an aspirator, designed to promote the outflow of fluid by suction into a partial vacuum.