HÆMATOX′YLIN

A principle obtained by Chevreul from common logwood ( Hæmatoxylon campechianum ), and on which its colour appears to depend. Prep. 1. Infuse logwood chips in water, at a temperature of about 130° Fahr., for 12 hours, filter, and evaporate to dryne in a water bath; digest the residuum in rectified spirit for 24 hours, again filter and evaporate; then add a little water; again gently evaporate and set aside the solution in a cold place that crystals may form; these must be washed in rectified spirit and dried. 2. Digest powdered hard extract of logwood in rectified spirit, and proceed as last. 3. Powdered logwood is mixed with sand and digested for several days in pure ether; the resulting liquid is filtered, evaporated to a syrup, and set aside to crystallise. Prop., . Brilliant reddish-white or straw-yellow crystals, soluble in boiling water, forming an orange-red solution which turns yellow as it cools, but resumes its former colour on being heated. Alkalies in exce change its colour succe ively into purple, violet, and brown; acids brighten it; with the metallic oxides it forms compounds having a blue, purple, or violet colour.