In the view of our present knowledge it is remarkable that Lancisi, in 1718, should have associated marshes with the development of gnats, which insects he thought could not only introduce with their proboscides the putrefying organic matter of such swamps but animalcules as well. In 1638 Countess del Chinchon, the wife of the Viceroy of Peru, was cured of an intermittent fever by the employment of the bark of certain trees which bark was introduced into Europe in 1640. The origin of the name cinchona is thus explained. While Morton and Sydenham in 1666 noted the specific action of cinchona in certain fevers it remained for Torti, in 1753, by the use of cinchona, clinically to differentiate those fevers which were cured by cinchona from those which failed to yield to this specific. Quinine was not introduced until after 1820. Audouard, in 1803, was the first to draw attention to the splenic enlargement of malaria. The views of Nott and Beauperthuis as to transmission of malaria and yellow fever by insects are considered under the latter disease. In 1847 Meckel announced that the dark color of malarial organs was due to a pigment and in 1848 Virchow noted that this pigment was contained in cells. In 1875, Kelsch observed pigmented bodies in malarial blood and in 1880 came to the conclusion that these pigmented cells were diagnostic of malaria. The year 1880 is the most important one in the history of malaria for on November 6, 1880, Laveran, at Constantine, first saw the parasites of malaria while carrying on investigations as to the origin of the pigmented bodies and melaniferous leucocytes. He not only noted the findings of spherical pigmented bodies but also of crescents and in particular the flagellation of the male gamete which demonstrated to him that these were living bodies. The name _Oscillaria malariae_ was proposed on account of the movements of the flagellate body, but had to be dropped as not valid, the generic name _Oscillaria_ having been previously applied. When these bodies were demonstrated to various Italian authorities, in 1882, they were thought by them to be degenerated red cells. It may be stated that at this time the Italians, influenced by the work of Pasteur, were convinced that an organism, _Bacillus malariae_, reported by Klebs and Crudeli (1879) to have been isolated from water and soil of malarious districts, was the cause of malaria. This bacillus was said to be cultivable on ordinary media and to be capable, when injected into man, of producing malaria.