distance of fifty yards, and avoiding the neighbourhood of stagnant pools and open cisterns of every description—it is quite possible to live in these tropical climates without the least fear of malarial fever. We believe that it will be found that a great source of danger is the planting of bananas and Indian corn near to the dwelling, as mosquitoes undoubtedly breed in such plants, which hold a great deal of moisture. The worst form of malaria, usually called black-water fever, is apparently conveyed only by the mosquitoes called Culexanopheles, and only the female can convey it. She makes a feed of blood during the breeding-season from a native or other person infected with malaria, and then injects the parasites into some other victim from whom she makes a second meal.
These are not the only difficulties in the way of colonisation. Insect enemies to plant life and cultivation of cereals are very numerous. Many experiments have ended
