That the opinion on the relation between the propagated sensation along me- ridians(PSM)and the age of the subjects was divergent in the results reported by some authors.In the last 10 years

we have performed a systematic investi- gation on PSM on a group of 536 youngsters.The main characteristics of PSM in youngsters were just the same as that of adults.However

the incidence of PSM in youngsters

particularly the degree of distinctness of PSM

was by far higher than that of adults

The results were stable and could be repeated in the experiments performed in different years.It showed that there was surely a close relation between the degree of distinctness of PSM and the age of subjects. This fact can not be appropriately explained at present.However

it provides an important clue to clarify the factors which influence the appearence of PSM

and in turn to promote the improvement of the therapeutic effect of acupucture fand cilacriation of the mechanism underlying the formation of PSM.