"It has been estimated that more than 1.6 million immigrants travelled to Australia by ship between 1788 and 1900. Nearly half were government-assisted and came primarily from Britain, albeit with smaller numbers from Europe and elsewhere. Yet in the first half of the nineteenth century the vast majority of the more than two and a half million souls who left the UK were destined for North America; only about 82,000 convicts and 75,000 immigrants, most assisted, made the long voyage to Australia between 1821 and 1840. This was extremely significant, however, in that before 1840 approximately three-quarters of Australia's non-Aboriginal population at some time in their lives made the long and tedious voyage from Europe. The principal focus of this paper is the general health of the convicts and immigrants, and particularly levels of morbidity (illness) and mortality (death) on the ships. Specifically, it addresses the interaction between convicts, immigrants and passengers on the one hand and the social and administrative structures on board on the other by examining the diseases, medical conditions, food and water supplies that prevailed among those who made the long sea voyage to Australia during the years 1837 to 1839."