Haematoxylum campechianum

Haematoxylum campechianum was used for a long time as a natural source of dye.[5] The woodchips are still used as an important source of haematoxylin, which is used in histology for staining.[5] The bark and leaves are also used in various medical applications. In its time, it was considered a versatile dye, and was widely used on textiles and also for paper.[6]

The extract was once used as a pH indicator. Brownish when neutral, it becomes yellow reddish under acidic conditions and purple when alkaline.[6] In a small demonstrative experiment, if two drops, one of concentrated ammonia and one of logwood extract, are placed close enough, the NH₃ vapours will change the color of the extract to a purple shade.[7]

Woodchips to use for histologic staining

Logwood also played an important role in the lives of 17th-century buccaneers and into the Golden Age of Piracy. Spain claimed all of Central and South America as its sovereign territory through the 17th and 18th centuries; despite this, English, Dutch, and French sailors recognized the value of logwood and set up camps to cut and collect the trees for shipment back to Europe. Spain periodically sent privateers to capture the logwood cutters – for example, Juan Corso's 1680 cruise – sometimes in retaliation for buccaneer raids on Spanish cities.[8] Logwood cutters, now out of work, frequently joined onto pirate and buccaneer crews to raid the Spanish in return, as Edmund Cooke did after losing two logwood-hauling ships to the Spanish.[9] When Spanish forces ejected a great many logwood cutters in 1715, they flocked to Nassau and swelled the already-considerable numbers of pirates gathering there.[10] By the mid-1720s logwood cutters had themselves become targets of pirates such as Francis Spriggs, Edward Low, and George Lowther;[11] pirate captains Samuel Bellamy and Blackbeard went further, turning captured logwood-hauling sloops into pirate vessels.[12] Logwood cutting was profitable – "According to a government report, in the four years 1713 to 1716, some 4,965 tons of logwood were exported to England at not less than £60,000 per annum" – but only brought in a fraction of the profits from tobacco and other legal exports, and "was always a minor industry carried on by a few hundred ex-seamen and pirates in a remote corner of the globe".[13]