The mustard gas experiments done by the British Homoeopathic Society for the Ministry of Home Security, 1941--1942

Following its military use during World War I, mustard gas was found to be not only a skin irritant, causing the well-known signs of blistering and conjunctivitis, but also a powerful cytotoxin that could compromise immune function by attacking blood-cell production in the bone marrow. The renewed threat of chemical attacks in the early years of World War II meant that research into prevention and treatment of mustard gas lesions assumed a high priority in the UK. The Ministry of Home Security asked homeopaths if they had any scientific evidence that homeopathic mustard gas ‘potencies’ could prevent or act as antidotes to the effects of the poison. In reply, the Council of the British Homoeopathic Society regretted that there was no scientific evidence of efficacy, but informed the Ministry that homeopathic physicians were calling for ‘gas potencies’ to be prepared for use in the event of a gas attack. The Council’s reply to the Ministry included a research proposal for trials if the Government provided support. The homeopaths’ decision to propose controlled trials appears to have been influenced by the Society’s President, John Paterson. He had been active in homeopathic clinical research in Glasgow, and he was confident that homeopathy would survive testing, despite the concern of some members of the Council that ‘negative’ results might jeopardise homeopathy’s position in the projected National Health Service. After receiving comments on the proposal from its scientific advisors, the Ministry agreed to co-operate, and the Society set up a ‘Gas Research Committee’, headed by Paterson and W. Lees Templeton, to coordinate the work of teams in Glasgow and London. Homeopathic (Greek homoios, similar) medicines are usually prepared from natural substances that provoke symptoms in healthy people like those seen in disease. For the intense itching, blistering and sores caused by mustard gas, a homeopath might prescribe poison oak (Rhus toxicodendron) or Spanish fly (Cantharides), for example. Another homeopathic approach, known as isopathy (Greek isos, same), treats the effects of a poison or other substance with the same substance in dilution. Both approaches were used in the mustard gas trials. As directed by the Ministry, the trials were done under carefully controlled conditions. The use of unbiased allocation to comparison groups, placebos to blind volunteers and those assessing the effects of treatment, and independent statistical analysis were all rare in the early 1940s. It is unclear whether these features of the studies resulted from the Ministry’s scientific advisers or from Paterson. The Ministry supplied a 10% solution of mustard gas in benzene, a 2-mm diameter drop to be applied to each volunteer’s forearm. Preparation of the skin, the area affected, surgical dressings and room temperature were all standardised. The outcome measured in all the trials was the visual assessment of lesions seven days after application.