The Collaborative International Dictionary of English v.0.48:

Galactin \Ga*lac"tin\, n. [Gr. ?, ?, milk. Cf. Lactin.]
   (Chem.)
      (a) An amorphous, gelatinous substance containing
          nitrogen, found in milk and other animal fluids. It
          resembles peptone, and is variously regarded as a
          coagulating or emulsifying agent.
      (b) A white waxy substance found in the sap of the South
          American cow tree (Galactodendron).
      (c) An amorphous, gummy carbohydrate resembling gelose,
          found in the seeds of leguminous plants, and yielding
          on decomposition several sugars, including galactose.
          [1913 Webster]