In 1847 Schleisner (b. 1818) was sent from Copenhagen to the Vestmanna Islands in Iceland to study the epidemic of tetanus neonatorum. The neonatal mortality in those islands at that time was 600-740 per 1000 children. He built a small hospital and introduced treatment with Peru balsam of the umbilicus. Schleisner probably assumed that the infection was caused by airborne infection, contact infection or poor hygiene. The neonatal mortality fell to about 50 per 1000. Schleisner published his results in 1849. Semmelweiss published his observations in 1850 and Snow successfully fought the cholera epidemic in London in 1854. Schleisner deserves recognition as a pioneer in the field of epidemiology.