為見諸經(jīng)中．無過與不及之病而有?。? 八十難曰．有見如入．謂左手見氣來至乃納針．針入見氣盡乃出針．非用迎隨補(bǔ)瀉之法不虛不實(shí)．不虛謂真氣未虛．不實(shí)謂邪氣未實(shí)．以此故自取其經(jīng)施其法也．