Studies on the phenomenon of latent propagated sensation along the channels. I. The discovery of a latent PSC and a preliminary study of its skin electrical conductance.

By combining electrical impulse stimuli with mechanical ones, we are able to trace out a new line of feeling, coincident with the classical channel course. Impulse stimulation was carried out at the Jing point of the Large Intestine or Stomach channel, namely Shangyan or Lidui. With a small rubber nipple, light taps were applied on the skin along the lines perpendicular to the channel and crossing over the acupuncture points; a specific propagational numb feeling at the points of the channel could be found. By linking up these points of specific feeling, an imaginary line which is exactly the classical Large Intestine or Stomach channel can be traced out. This line is called the "latent propagational sensation line along the channels" because, unless through tapping, no prominent sensation of propagation could be felt. Employing an impulsive electrical generator and an all-wave commutating circuit linked to a micro-ammeter, the skin conductance was measured over the latent PSC of the Large Intestine channel lying between the wrist and 5 cm above the elbow joint. Results were compared to those locations of 1 cm apart from the channel course, i.e. the control sites devoid of acupuncture points or channels. At most acupuncture points or any site of the channel course on all of the 10 subjects under examination, there was greater electrical conductance maxima than there was at control sites. This fact indicates that not only the acupuncture points, but the entire course of latent PSC are also of higher electrical conductance.