Abstract
In late 18th century Britain, typhus fever plagued the mass mobilisation of soldiers and posed a significant challenge to physicians of the time. Epidemic typhus was spread through highly infectious faeces of infected lice and carried a high mortality in patients and healthcare staff alike. Physicians James Carmichael Smyth (1741-1821) and Archibald Menzies (1754-1842) theorized that typhus fever was caused by infection of human exhalation. They trialled the use of vapourised nitrous acid to fumigate patients, their clothes and their bedspace, with apparent success. Despite this, typhus fever continued to ravage deployments of soldiers into the early 19th century, stimulating the continuing evolution of the understanding of typhus and its treatment.