Nine days

I was trying to work today. Really. I was. But then I was distracted. By a rhyme. Suddenly I was thinking about porridge.

Pease porridge hot,
Pease porridge cold,
Pease porridge in the pot
nine days old.

I remember hearing this rhyme as a child and finding it rather baffling. It was the last rhyme in the book. I didn't like porridge. The prospect of being served porridge that was not only cold (and therefore revolting and glutinous), but was also old filled me with disgust. And I could only imagine it a couple of hours old. In my small imagination nine day old porridge was practically green with mold and pungent smells. It was obviously memorable, since someone made a rhyme about it.
The illustration in my rhyme book showed a matronly woman in old fashioned-y dress benignly smiling and stirring a pot of (presumably) porridge. Was this woman proposing to serve the innocent children in the corner porridge that was nine days old? Why should she do such a thing? Had the children been bad? If I was bad would Dad serve me old porridge? The whole scenario struck me as sinister.