Abstract: In accordance with the invention there is provided a petri dish comprising a container for the growth of microorganism cultures and a lid for the container to prevent the entrance of contaminants, each of the container and lid having a radially outwardly extending flange, these flanges and the container and lid being so shaped and dimensioned as to enable easy manual removal and reapplication of the lid to the container with the use of only one hand by the person tending to the petri dish thereby leaving the other hand free to administer the microorganism specimen and other ingredients to the dish.

Abstract: In accordance with the invention there is provided a mouth filter for use with pipettes to insure that none of the liquid or any of the bacteria in the liquid being drawn into the pipette reach the mouth of the technician applying the suction. The filter comprises an organic resin housing having a filter membrane therein which divides the housing into an inlet chamber and an exit chamber, the filter membrane being hydrophobic and constituting a bacteria barrier. The housing has tubular extensions extending from the oppositely disposed axial end walls thereof. A tube is secured to one extension of the housing and is adapted to be secured in communicating relationship with a pipette into which the liquid is to be drawn. Connected to the other housing extension is a mouthpiece for mouth-applied suction by the technician, which suction is communicated through the filter membrane and tube to the pipette.