The invention relates to a method and apparatus for measuring the responsiveness of a subject with lowered level of consciousness. lower than that of the good solvent, wherein the ground substance is dissolved in the solvent. The sealing member is also enabled to be displaced in a horizontal plane with respect to the longitudinal axis defined by the cannula member. The rings engage with the posts respectively and elastically abut against an upside of the motherboard. The first detector are embodied to produce an electric field in the detection space, and the detection space is embodied to comprise a gas.