Xanthin \Xan"thin\, n. [Gr. xanqo`s yellow.]
   1. same as xanthine.
      [1913 Webster]

   2. (Chem.) A yellow insoluble coloring matter extracted from
      yellow flowers; specifically, the coloring matter of
      madder. [Formerly written also xanthein.]
      [1913 Webster]

   3. (Chem.) One of the gaseous or volatile decomposition
      products of the xanthates, and probably identical with
      carbon disulphide. [Obs.]
      [1913 Webster] Xanthine

Xanthine \Xan"thine\, n. Also Xanthin \Xan"thin\ . [Gr. xanqo`s
   yellow.] (Physiol. Chem.)
   A type of purine obtainable as a white microcrystalline
   powder, C5H4O2N4, present in muscle tissue, in the liver,
   spleen, pancreas, and other organs, and also in urine (in
   small quantities) and some urinary calculi, and in the juices
   of certain plants; -- so called because it leaves a yellow
   residue when evaporated to dryness with nitric acid. It is
   also present in guano. Xanthine is closely related to uric
   acid.
   [Webster 1913 Suppl.]