Abstract: A multiwell tissue culture assembly comprises a plate and a lid. The plate includes a plurality of wells for receiving liquids therein. Upstanding side walls form the outside border of the plate. A ledge is spaced inwardly of the side walls and extends around the plate between the side walls and the wells. The lid is removably positioned on the plate and includes a substantially planar cover extending over the wells. A labyrinth passage is associated with the cover, the side walls, the ledge and the wells to permit air exchange between the wells and the external environment to maintain equalibration therebetween, but to partially prevent air entrance to the wells to minimize evaporation of liquids in the wells.

Abstract: A device for stirring liquid in a rotating container includes a movable stirrer adapted to be positioned inside a rotatable container and to impart stirring movement to liquid placed therein. A gravity-induced stirring mechanism is associated with the container and the stirrer for moving the stirrer with the container for only a portion of a revolution of the container when rotating. This mechanism permits the increasing gravitational force thereon due to rotation to discontinue the movement of the stirrer and cause a gravitational rotation of the stirrer in a counter-direction to that of the rotating container whereby liquid inside the container is stirred.

Abstract: A roller bottle for cell growth culturing comprises an outer housing defining a hollow chamber therein. At least one annular member is inside the chamber spaced a short radial distance inwardly from the housing. The space between the annular member and the housing is in fluid communication with the chamber. The surfaces of the annular members and the interior surface of the housing are adapted to grow cells thereon.