Final answer:
The reference provided does not Text Interpretation mention 'mustard water.' It discusses John's care for his wife by giving her cod-liver oil and other nutritional supplements.
Step-by-step explanation:
The question “Why does John drink mustard water?” appears to be based on a misinterpretation of a text, possibly as a result of a typo or other error.
There is no mention of “mustard water” in the provided reference. Instead, the character John is mentioned to have his wife take cod-liver oil, tonics, ale, wine, and rare meat to ensure she does not lose her strength.
The text indicates that John is very caring and does not want his wife to be sick, fostering her health with various nutritional supplements, but “mustard water” is not one of them.