In the early 1920s patients diagnosed with pernicious anaemia faced a di cult future. e symptoms of the disease included weakness, pallor and yellowness of the skin and fatigue; patients experienced palpitations of the heart and breathlessness when they attempted physical e ort, troubling disturbances of the digestive system, including sore mouth, sore tongue, vomiting and diarrhoea, and numbness of the lower extremities. Even worse, most patients died within one to two years a er learning about their disease. As science writer Paul de Kruif memorably remarked ‘in 1925 being told you had pernicious anaemia meant the undertaker for you more surely than if the governor had signed your death warrant for rst degree murder’.1