them with veils and protections. It is setting itself to extirpate the very instruments of the propagation of the disease. Its enemy is the insect. That extraordinary populous and intelligent kingdom might have once attained the supremacy of the world, but for some inexplicable limitations in size which has prevented any of its denizens from challenging the forces of mankind. Michelet has described the kind of horror with which the head of an ant inspired him, as first seen under the microscope; with its vast and complicated eyes, its evidence of incalculable brain power, but with the utter absence of any of those human qualities which are revealed even in the vertebrate animals. Yet those ants can exhibit inexplicable powers of communication, and a social organisation which has been the envy of many a philosopher, as he contrasts it with the chaos of human life. Ants charged with “Boom food,” ant communities of many thousands, all six feet high, might provide a considerable obstacle to the accepted supremacy of mankind. But the insect, however tiny, is becoming more and more to be recognised as one of the enemies of the human race. There is here no possibility of compromise. We can be sentimental over the horse, the cat, the dog. If we are sentimental over the insect, we are lost. “Why should I harm thee, little fly?” was Uncle Toby’s famous inquiry. “Is there not room enough in the world for me and thee?” Science is unhesitatingly pronouncing a grim negative to the question. There is not sufficient room in the world for “me and thee.” This is probably true of the common house-fly, who more and more is coming to be branded as a propagator of disease. It is already accepted of his cousin, the mosquito, against whom the whole of the world is turning with a set purpose of extermination. The alleged unhealthiness of marshes and tropical regions, formerly ascribed to heat and noxious vapours, is now declared to be entirely explicable by the spread of a definite bacterium through the bites of insects. Where the insects are destroyed the white man flourishes. Panama, in the early days of the Canal building, was converted into a visible hell, in which a population rioted and rotted and died, as they rioted and rotted and died in the days of the plague. The Americans to-day have descended there with all scientific resources. They burn the insect, they choke its offspring with oil, they drain the stagnant pools where it can breed, they consume it in clouds of evil-smelling smoke. They are rapidly making Panama a healthier place than New York or Chicago. All down the coast of South America, yellow fever has decimated mankind for centuries. To-day it is well on its way to becoming a thing of the past. Six years ago an international campaign was inaugurated against the _Stegomya fasciata_, the “white-ribbed mosquito,” which spreads the disease. At Rio Janeiro, Dr. Cruz, “Cruz the mosquito killer,” has practically removed its menace.