An ink for ink jet recording which inclides a water-insoluble ionic group-containing polymer added to a colored fine particle dispersion containing at least a hydrophobic high-boiling organic solvent having a boiling point of 150 C. In one embodiment, the method comprises receiving a signal containing data representing a plurality of pulses, the signal generated in response to detecting light scattered from blood perfused tissue. The optical system is movably mounted on the unit base and can be adjusted by means of at least one drive. The proximal region of the ultrasound transmission wire has a larger diameter than the intermediate region, the intermediate region is continuously tapered with a progressively decreasing diameter from its proximal end to its distal end, and the distal region has a greater diameter than the distal end of the intermediate region. Said aqueous compositions are preferably homogeneous aqueous solutions.