Pneumogastric

[…]were it not for a strange-smelling, at first not unpleasant, but with the passage of time frankly revolting vapour arising from among the recesses of Mr. Magershon's body-linen and issuing, with great volatility, between his nape and his collar-band, a bold and it must be allowed successful effort on the part of that dignitary's pneumogastric to compensate the momentary confusion of its superior connexions.