An analyzing cartridge and method for using it to analyze a sample having
a plurality of reservoirs and capillaries connected for communication
between these reservoirs and is provided therein with a reagent required
for analysis. The reservoirs are provided with openings leading to the
outside of the cartridge, and the openings are covered with vents each
consisting of a gas-permeable/non-liquid-permeable, hydrophobic, porous
membrane. The analyzing cartridge requires only trace amounts of a sample
and a reagent and no maintenance. It is provided with a non-fluid reagent
in vent-carrying reservoirs thereby making it possible to formulate a
very trace amount of reagent solution in the cartridge by injecting a
reagent dissolving liquid into the reservoirs immediately before
analyzing. A liquid feed control device controls the feeding of the
liquid between the reservoirs via the capillaries when it is attached to
the cartridge to allow or control the entry/exit of air via the vents.