"Organic mercury is in the form of a mercury ion (inorganic mercury) with an
organic group stuck onto it. Such as the ethyl group in ethylmercuric
thiosalicylate, trade name Thimerosal or Merthiolate. Your body slowly
converts organic mercury to inorganic mercury. The half life of
methlymercury is 44 days - mostly it is converted to inorganic mercury in
your body before it is excreted. Organic mercury crosses the blood brain
barrier easily."