The Collaborative International Dictionary of English v.0.48:

Haematoxylin \H[ae]m`a*tox"y*lin\ (-t[o^]ks"[i^]*l[i^]n), n.
   [See H[ae]matoxylon.] (Chem.)
   The coloring principle of logwood. It is obtained as a yellow
   crystalline substance, C16H14O6, with a sweetish taste.
   Formerly called also hematin.
   [1913 Webster]