Bolton, George Buckley, Esq., Member of the Royal College of Surgeons, and of the Medical and Chirurgical Society of London. Statement of the principal circumstances respecting the united Siamese Twins now exhibiting in London. Philosophical Transactions of the Royal Society of London, Part I, pp. 177-186, London: 1830.
Chang and Eng Bucker were born in Siam (now Thailand) in 1811. Originally the King of Siam had ordered them killed as “monsters” but then realizing they were quite harmless he rescinded the order. They were subsequently discovered by a British merchant Robert Hunter and a Captain Coffin. Permission was obtained in March 1829 to take the twins to England where they were exhibited at concert halls and theaters.
At age twenty-one they were able to claim their independence and continue their performances and anatomical auditions. Both were married and sired 21 children between them. At the time of their deaths they were living in the U.S. on two farms a mile apart and spent a week apiece at each farm.
They remained in circuses and performances right up to their deaths. They were autopsied at the time of the deaths and found to have conjoined livers and part of the gall bladder system. So in the pre-anesthesia and pre-antiseptic era they would likely have not survived a separation attempt. They were examined on many occasions by physicians with various reports appearing and this one, done at the age of 19, is one of the earliest done by a respected physician.