A method and composition for probing the body through the skin. A solenoid valve device for opening and closing an output flow path for pressurized fluid includes the solenoid portion, the valve body portion 3 in which valve seats are formed to be elongated in the direction of arrangement of the plurality of solenoids, and a movable valve made of a paramagnetic material to open and close the valve seats. The second bias generating circuit generates a second substrate bias voltage of N-channel transistor. The output of the detector is a sinusoidal signal having the same phase as the phase of the optical test signal. Such methods and compositions are useful for facilitating processes such as, for example, transcription and recombination, that require access of exogenous molecules to chromosomal DNA sequences.