A device for quantitively collecting, preserving and mailing a specimen of fecal or other biological matter for later analysis comprises a tubular vessel defining a chamber closed at one end by a plug and restricted at the opposite end by a narrow aperture. A stopper for closing the open end of the vessel extends into a stick having indentations capable of retaining some of the biological matter. The stick intimately engages the aperture so that the amount of matter introduced into the chamber is limited to what is carried in the indentations. The shank of the stick seals the aperture once the stopper has been screwed into place. The plug mounts a breakable hollow nib and is installed after introduction into the chamber of a metered volume of preserving solution. A cover caps the plug and nib to provide additional sealing of that end of the vessel.