只消一釐 Enough To Kill A Mortal
道士對七個女子道：「妹妹，我這寶貝，若與凡人吃，只消一釐，入腹就死；若與神仙吃，也只消三釐就絕；這些和尚，只怕也有些道行，須得三釐。快取等子來。」道士对七个女子道：「妹妹，我这宝贝，若与凡人吃，只消一厘，入腹就死；若与神仙吃，也只消三厘就绝；这些和尚，只怕也有些道行，须得三厘。快取等子来。」
逐句解 Line by line
The Daoist said to the seven women, "Sisters, this treasure of mine — give it to an ordinary man and one lí is all it takes; it reaches the belly and he is dead;"
寶貝, treasure, is what he calls it, and the affection is real. 妹妹 reduces its second syllable, as the whole class of doubled kinship words does — 哥哥, 爺爺, 姐姐 among seventeen registered in all. A 釐 is the smallest weight in ordinary use, a tenth of a 分, and 凡人 is a plain mortal as against an immortal.
"give it to an immortal and three lí will finish him;"
絕 is to cut off, to end — blunter than dying. The scale he is sketching is a dosage table, and its top row is gods.
"these monks, I dare say, have some attainment of their own, so three lí will be wanted."
道行 is dào héng, and it is the only 行 in this chapter's seventy-four that is neither xíng nor háng. It means accumulated spiritual attainment — what a practitioner has actually built up, as against what he claims. The reading catches people out constantly, and the pipeline now guards the whole distribution rather than just the háng band.
"Fetch the scales, quickly."
等子 is a small steelyard — a balance with a sliding weight on a marked arm, used by apothecaries and moneychangers for weighing tiny quantities. He is not estimating. He is going to weigh it.
This is the passage where the chapter turns cold, and it does so by being technical. He is not raving about revenge; he is giving a dosage. One lí for a mortal, three for an immortal, and monks with some practice behind them rate the immortal dose. The compliment buried in that is the nastiest thing he says.
It is also, unexpectedly, careful. He asks about their attainment, adjusts upward, and calls for scales. A man who wanted them dead any old way would use more. This one is going to weigh out exactly enough, because the stuff is expensive and he made it himself.
道行 deserves the note it gets. The word means what you have actually accumulated through practice, and it is the standard yardstick in Chinese religious fiction for how hard someone will be to kill. He is estimating the 道行 of four men he has met once, over tea, and he is about to get the estimate very badly wrong about one of them.