But the doctor said: 'Lots of children are like that. Don't worry. There's a scientific test that pediatricians do to see if children are taking in enough nutrients.'
He gripped my daughter's fat cheek and gave it a shake. 'That's the test. And here's the result: She's fine.'
This comforted me, although I would have preferred a more scientific answer. I found that last weekend in a biology textbook belonging to my son. This introduced me to 'air plants'small, fern-like clumps of vegetation which extract nutrients directly from the atmosphere. Clearly, my youngest child is an Air Baby, extracting everything she needs from the semi-visible stuff which passes for air in Hong Kong.
My son reckons his little sister has developed the ability to photosynthesize light. I liked this idea. 'If plants can do it, I don't see why she can't,' I theorized. 'After all, she's smarter than most vegetables.' (He disputed this.)
There's one other strange thing about Child Three. She regularly manages to produce more than her own weight in liquid on occasion.
Since she is trying to get out of the habit of wearing night-time nappies, we limited her intake of liquid. Despite this, she managed to produced a Noah-like deluge which flooded her bed by in the morning. We dried her off and put her into our bed for the rest of the night. Lo and behold, at four in the morning, she managed to unleash a second Tsunami, turning our bed into a life-sized replica of the Pok Fu Lam reservoir. One of our pillows is made of foam, and it was bobbing around, as if on a lake.
'Where did all that come from?' my wife asked. 'How can a 20 kilo child have a 25 kilo bladder?'
The mystery was solved at dawn, thanks again to my son's biology textbook. Some plants use their entire bodies to store liquid, it said. Having acquired the ability to photosynthesize energy from light, she is apparently moving on to other botanical skills.