Yesterday I was planning on writing about MC Spleen, a French rapper and beat-boxer extraordinaire with a great name. But almost better than a rhymer named after everyone’s favorite lymph organ is Dr. John Clarke, the medical director for New York’s Long Island Railroad who recently won a contest put on by the Center for Disease Control to create an infectious public service announcement about H1N1 flu. New York magazine gives him props for rhyming “hand sanitizer” with “I advise ya,” and when I heard him on NPR yesterday he also rapped about asthma, with an impressive integration of icky lyrics about mucous.