In a paper read before the Philosophical Society of Washington, Feb. 10,1883, Dr. A. F. A. King endeavored to sustain the thesis that malarial disease is produced by the bites of insects inoculating the body with malarial poison, the mosquito being considered in this country the most,active agent. Whatever value may be ascribed to mosquito bites as a cause of disease (and there are several very strong and, to our mind, fatal objections to the theory, and especially the fact that malaria prevails at seasons when no mosquitoes occur), it is interesting to observe how the properties and phenomena usually ascribed to malarial vapors become susceptible of explanation on the above insect theory, and how easily coincidences are made out. In the course of his remarks he presented the following series of twenty statements culled from leading medical authorities, in relation to malaria, and which, he maintained, are explicable on the mosquito theory. 1st. Malaria affects by preference low and moist localities. Such localities are the natural abode of mosquitoes. 2d. Malaria is seldom developed at a lower temperature than 60 F. ; neither are mosquitoes. 3d. The active agency of malaria is checked by a temperature of 32 F. The same may be said of the mosquito. 4th. Malaria is most abundant and most virulent as we approach the equator and the seacoast. So, under specified conditions, are mosquitoes. 5th. Malaria has an affinity for dense foliage, which has the power of accumtilating it, when lying in the course of winds blowing from malarious localities. Trees accumulate mosquitoes In the same manner. 6th. Forests and even woods have the power of obstructing malaria and of preventing its transmission under these circumstanees. So of mosquitoes. 7th. By atmospheric currents, malaria may be transported to considerable distances, probably as far as five miles, Mosquitoes also. 8th. Malaria may be developed in previously healthy places by turning up the soil, as in making excavations for the foundations of houses, tracks for railroads and beds for canals. Such excavations when containing stagnant water may also serve as mosquito nurseries. 9th. In certain localities malaria seems to be attracted and absorbed by bodies of water lying in the course of such winds as waft it from miasmatic source. Such bodies of water may also arrest the passage of the mosquito, under certain circumstances, as in the absence of a strong wind to waft them over. lOtb. Experience alone enables us to determine The presence or absence of malaria in any given locality. Conversely, The absence of The mosquito, it was claimed by Dr. King, appeared to prevent malarial disease. lltb. In proportion as countries previously malarious are cleared up and thickly settled, periodical fevers disappear. The consequent better drainage, disappearance of underbrush, and the more free play of fly catching birds may also contribute to lessen mosquitoes. 13th. Malaria usually keeps near the surface of the earth; it is said to "hug the ground." The same is true of mosquitoes. 13th. Malaria is most dangerous when The sun is down, and seems to be almost inert during the day. The mosquito is active at night; at rest by day. 14tb. The danger of exposure to malaria after sunset is greatly increased by the person exposed sleeping in the night air. Persons while awake brush away mosquitoes; those asleep submit to being bitten. 15tb. Of all human races the white is most sensitive to marsh fevers, and the black least so. The black man is less easily seen by The mosquito, and The odor and greasiness of his cutaneous secretions ai'e assumed to be offensive to the insects. 16th. In malarial districts The use of fire, both indoors and to those who sleep out, affords a comparative security against malarial disease. Mosquitoes, attracted by the light, fly into fires and lamps at the cost of life. 17th. The air of cities in some way renders The malarial poison innocuous, for though a malarial disease may be raging outside, it does not penetrate far into the interior. Mosquitoes also, during their nocturnal flight, will be arrested by the houses, fences, lamps, and fires of The suburba, so as to be prevented from penetrating far into the interior of cities. 18tb. Malarial diseases are most prevalent toward the latter part of the summer, and in the autumn. Mosquitoes are more plentiful during those seasons. 19th. Malaria is arrested not only by trees, but hj walls, fences, hills, roWs of houses, canvas curtains, gauze veils, mosquito nets, etc. So are mosquitoes. 30tb. Malaria spares no age, but it affects infants' much less frequently than adults. Infants, however, from the care with which they are housed and covered with gauze to keep off house flies, and also shielded from mosquito bites. C. V. R.
This article was originally published with the title "Malaria" in SA Supplements 15, 380supp, 224-225 (April 1883)