The Collaborative International Dictionary of English v.0.48:

Cerebrin \Cer"e*brin\, n. [From Cerebrum.] (Physiol. Chem.)
   A nonphosphorized, nitrogenous substance, obtained from brain
   and nerve tissue by extraction with boiling alcohol. It is
   uncertain whether it exists as such in nerve tissue, or is a
   product of the decomposition of some more complex substance.
   [1913 Webster]