Santa goes into a chemist's shop, reaches into his pocket and takes out a small bottle and a teaspoon. he pours some liquid onto the teaspoon and offers it to the chemist, "could you taste this, please?"
the chemist takes the teaspoon, puts it in his mouth, swills the liquid around and swallows it.
santa: does it taste sweet?
chemist: no, not at all.
santa: good. the doctor told me to come here and get my urine tested for sugar.