Lately the_child has been asking a lot of questions about cancer. We've discussed the basic mechanism (cell division error), the primary treatments (surgery, chemotherapy and radiotherapy), the idea that there are many sorts of cancer and it's not a unitary disease at all. These conversations are episodic, and she returns to the topic from time to time.

Last night she asked me if the cancer of one of her friend's mothers would return. I said I had no way to know, but this led to a discussion of metastasis, and the preference of certain cancers for specific organ systems. For example, mine is colon cancer, tubovillous adenocarcinoma, with a strong metastatic preference for lymph, liver and lungs, so we discussed how my metastases were unlikely to occur in my brain or my stomach or my kidneys.

Then she asked a question that surprised me considerably. "Does cancer go where there are the most nutrients, or where the body is weakest?"

Somebody's been explaining the germ theory of disease to this child.

So we talked about the difference between diseases with external vectors, ie, infections, and cancer, which is a mistake the body makes in its own internal processes and not dependent on the same factors as viral or bacterial infections. She informed me that our bodies had plentiful germs naturally that belonged there, which I allowed as how this was true. I compared resident intestinal flora to opportunistic rhinovirus to illustrate her point.

Sometimes the_child is my little girl, sometimes she's a sophisticated thinker. Well, really, she's both all the time, but the emerging adult, visible down the long, difficult hallway of stormy adolescence, drops in occasionally to surprise me most pleasantly.