Abstract: A method and apparatus for inserting a soft pliable prosthesis, such as a mammary prosthesis, into a human body through an incision. A prosthesis to be inserted is contained in an open mouthed inner bag of flexible fluid impervious sheet material and in a preferred form of the invention, a second outer open mouthed bag of similar material is sealingly joined to the inner bag at the mouths of the bags by means of a ring member seal. The outer bag carries a charge of fluid. The ring member is provided with a flange which may be seated in an open incision, and upon squeezing of the outer bag, the pressure applied to the fluid in the space between the two bags everts the inner bag through the ring member to carry the prosthesis contained therein to the desired position within the body.