At the pharmacy

La perfusion is the entry on this page an English reader is most likely to misread, because the word exists in English and does a different job there. In a hospital, « perfusion » is blood arriving in a tissue: a surgeon speaks of « the perfusion of a kidney », and « a poorly perfused foot » is one the circulation is not reaching. French took the bare noun away from the tissue and gave it to the equipment. La perfusion is the drip — the bag on the stand, the line, the slow hours — so le patient est sous perfusion says the man is on a drip and says nothing whatever about his circulation. The physiological sense survives in French only inside a compound, la perfusion tissulaire, where the second word carries it. Watch the neighbouring pair as well, because it blocks the obvious repair: the English word for that same bag is « infusion », and French une infusion is herbal tea, lime blossom or camomile after dinner, never anything attached to a vein. So both words are shared and neither can be carried across unchanged.