一股穢氣 A Reek On The West Wind
但刮西風，有一股穢氣，就是淘東圊也不似這般惡臭。如今正值春深，東南風大作，所以還不聞見也。」三藏心中煩悶不言。但刮西风，有一股秽气，就是淘东圊也不似这般恶臭。如今正值春深，东南风大作，所以还不闻见也。」三藏心中烦闷不言。
逐句解 Line by line
"Whenever the west wind blows there comes a reek off it, and even the dredging of a privy does not stink like this."
The comparison is a privy being dredged out, and the old man's point is that it does not come close. 東圊 is the polite word — literally the "east privy," the euphemism placing it on the far side of the courtyard. 似 is fixed at sì across the corpus; since that and the alternative reading carry the same tone, the 不 in front of it is unaffected and stays bú.
"Just now it is deep spring and the wind is blowing hard from the south-east, which is why you cannot smell it yet."
還 is hái, "still" or "yet" — not the huán that means giving something back. Both readings are common and only context sorts them.
Tripitaka was troubled in his heart and said nothing.
中 is zhōng in 心中, "within the heart." 煩悶 is a settled, inward vexation — the feeling of something sitting on you, not a sudden shock.
The old man's last stroke is his best one. He never describes the smell. He measures it against the worst thing his listeners can be expected to have smelled and reports that the comparison is inadequate.
Then he adds the detail that makes it real: the wind is in the wrong quarter today, so they cannot smell it yet. An obstacle that is both present and undetectable is a more unsettling thing to be told about than any description would have been.
The scene ends with Tripitaka silent. He has asked all the questions and now has his answer, and the narrative gives him no speech at all — an inward state and an absence of words. The season named here, deep spring, is the same one the chapter opened on.