_Treatment._—Rest in bed as soon as possible; free purgation at the outset; an early dose of twenty to thirty drops of laudanum (Tinct. opii) is often very beneficial but the drug must be administered with care. Aspirin in ten-grain doses thrice daily frequently relieves the more urgent symptoms. In cases where there is vomiting and collapse with high temperature a dose of fifteen grains of aspirin with half to one ounce of brandy and three drachms of liquor ammon. acetat. may act like a charm. According to our present knowledge, however, it would seem that drugs are of little use in influenza, and that the important thing is to ensure good nursing and to keep up the patient’s strength. Quinine in effervescing form is very useful for convalescent cases. _Insect Pests._ (_See also Myiasis and Skin Diseases._) These are best divided into the Winged and Wingless forms. Of the winged pests _Mosquitoes_ are undoubtedly the most important in the tropics, as they are known to transmit such diseases as malaria, yellow fever, dengue fever and filariasis. The anopheline mosquitoes are those responsible for transmitting malaria, and they can easily be recognized by the facts that their wings are usually spotted and that they appear as it were to stand on their heads when resting on any flat surface. The culicine mosquitoes, which include _Stegomyia fasciata_, the carrier of yellow fever, do not as a rule have spotted wings and they rest parallel to the surface on which they alight. There are also marked differences in the water stages of these insects which cannot, however, be here considered. The best way of protecting oneself against mosquitoes is the proper use of an effective mosquito net, the mesh of which should contain at least sixteen holes to the linear inch. Mosquito boots or buskins are also useful, and in certain places hoods for the face and neck, such as the “Mosquinette” variety, will be found of value. Repellent substances applied to the skin may also be employed. Cassia oil, with brown oil of camphor in vaseline, is useful. Vermijelli, containing a little citronella oil, is fairly effective but is not so pleasant to use. The irritating effect of mosquito bites may be diminished by the application of tincture of iodine. The same measures are effective in the case of some of the biting midges. The insects generally known as _Sand-flies_ are really owl midges or moth flies, tiny and hairy insects which have been proved to transmit sand-fly fever (_see_ page 221). These flies breed in damp places where there is rotting vegetation, dark and damp cellars, cracks and fissures in the soil, tunnels, etc., and they are often very troublesome. The repellents mentioned above may be used to drive them away, as may eucalyptus oil, camphor and tobacco smoke. The ordinary mosquito net is useless against their attacks, and one containing twenty-two holes to the linear inch is required.