Before 1780 there was no public provision for the hospital treatment of fever patients, “St. John’s being the first building of the kind erected in the empire”. They suffered and died in their homes under the combined pressure of poverty and disease. The spread of fever was controlled by admitting patients to hospital and isolating them from the rest of the community. Epidemics were frequent. This Irish study deals to a large extent with the 1820s, the cholera epidemic of 1832 and with the Great Famine of the 1840s―a period when St. John’s Hospital admitted more than 5,000 fever-ridden patients.