there is here provided a convenient bag used at the time when microorganisms which adhere to a specimen containing a solid material are extracted with a saline solution and are then examined . in this bag , a filter sheet is stuck to plastic film sidewalls so as to extend from the opening inlet to the bottom portion of the sidewalls , so that the bag is divided into two chambers . a specimen and a saline solution are poured into one of the two chambers , and the resulting extract is taken out by a pipet from another chamber .