Propagation of light along a pericardium meridian is measured and compared with that along a non-meridian path one cm away from the meridian. Source-light is illuminated on the Nei-Guan(PC6) and propagated light is detected at three points along the meridian. Four reference points are one cm away from the corresponding meridian points, respectively. Light propagates better along the meridian than the reference path with more than twenty percent difference for all the subjects tested.