Abstract: A vacuum bottle for collection of pus has a vessel of pressure- and tempeure-resistant plastic material. The outlet of the neck of the vessel is surrounded by a collar which has a plane end face and extends radially outwardly beyond the external surface of the neck, the same as an annular rib which is spaced apart from the collar. The end face is adjacent a membrane-like end wall of a cupped elastic cover having a cylindrical skirt which surrounds the neck and has an internal shoulder engaging an external shoulder of the rib to separably couple the cover to the bottle. The end wall is connected with one end of a conduit the other end of which can draw pus from a wound. The pressure in the vessel is reduced below atmospheric pressure by heating the vessel so that the air therein expands and escapes between the neck and the skirt of the cover. The vessel is thereupon cooled whereby the end wall penetrates into the outlet and sealingly engages the end face of the collar.