Introduction: Therapeutic bloodletting has been practiced at least 3000 years as one of the most frequent methods of treatment in general, whose value was not questioned until the 19th century, when it was gradually abandoned in Western medicine, while it is still practiced in Arabic and traditional Chinese medicine.
By the time of the 1918–1919 pandemic, it was common practice to put the sick outside in tents or in specially designed open wards. Among the first advocates of what was later to become known as the “open-air method” was the English physician John Coakley Lettsom (1744–1815