The case of the “Eclair,” and the history of the Epidemic Fever which occurred at Boa Vista in 1845, have been declared by high medical authority to afford “conclusive evidence that Yellow Fever is sometimes imported.” It will therefore be necessary to make a careful examination of the circumstances relative to this Epidemic. It has been affirmed, and generally credited, that unusual effort has been made to ascertain the facts of this case under circumstances more than commonly favourable to the discovery of the truth. Two official Reports respecting it, drawn up after personal inspection on the spot, have indeed been presented to Parliament—one by Dr McWilliam, and the other by Dr King; and several official notices of these reports have been published; but the evidence on which these two Reports were founded was not collected until some time after the cessation of the epidemic. The statements of witnesses, for the most part poor and ignorant, many of whom had a direct interest in establishing the importation of the disease by a British ship, have been admitted implicitly, even with respect to dates and circumstances not of recent occurrence, and without due examination of the credibility of their testimony; and on all material points the reporters have arrived at directly opposite conclusions. On a review and comparison of the whole of the statements which have been made with respect to this case, it appears that the steam-ship “Eclair,” with a crew of 140 officers and men, proceeded in 1844 to the coast of Africa, and was stationed for upwards of four months (130 days) at the island of Sherboro, with a view to blockade the eastern outlet of the passage at Shebar. This place is considered one of the most unhealthy on the African coast; vessels remaining near the island very rarely escaping an outbreak of Yellow Fever on board. The land is represented as low lying, some parts being marshy, and the rest thickly wooded, and abounding in rank vegetation. According to the account of the surgeon of the “Eclair,” Mr Maconchy, the ship on this occasion was anchored at the mouth of the river, in position where she “was surrounded with filthy-looking river water, urged backwards and forwards by the tides through extensive tracts of mangrove bushes.” The fresh water used on board was also bad, holding in solution a quantity of offensive vegetable matter, which produced in some of the crew attacks like mild cholera. The men, in parties of from 30 to 40, were often sent up the river on boating expeditions, where they remained for seven or eight days at a time exposed, “whether they slept on board or ashore, perhaps after a hard day’s labour, to all the exciting causes of fever, and a tainted nocturnal atmosphere, in the rainy season, heavy weather having set in, and the men constantly getting as wet as possible.” The danger of this boating service is thus stated by Dr King:—