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Page:Popular Science Monthly Volume 57.djvu/322

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POPULAR SCIENCE MONTHLY.

these two bodies to the life of the parasite? Their nature and purpose do not receive any illumination from Golgi's theory. You will find in all forms of malarial infection, if you look enough, the flagellated body; but, strange to say, you will not find it in malarial blood immediately after it is withdrawn from the body. It is only after an interval of minutes, perhaps a quarter of an hour, after the blood is withdrawn that these flagellated bodies appear. Whence do they come? If you make a preparation of malarial blood from a patient by pricking the finger and spreading a little of the blood on a slide, fixing it immediately with heat or alcohol and staining it, you will never see any of these flagellated organisms. But if the slip be kept moist and in a warm temperature for half an hour and then stained, the flagellated bodies will be seen, proving that they develop only after the escape of the parasite from the human body. Such a fact is very interesting and obviously has some significance in connection with the life of the parasite. Whence, I ask, come these flagellated bodies? If one of the crescent-shaped bodies is observed continuously, the following changes of shape may often be observed: It becomes shorter, loses its crescent shape and gives off flagella, which may break off and swim about by themselves. When they come in contact with a blood corpuscle they straighten themselves out and indulge in a peculiar vibratory movement, as if endeavoring to penetrate the corpuscle.

Many years ago King, in America, and others too numerous to mention suspected that the mosquito had something to do with malaria, but in what way they could not say. Not only civilized observers had this suspicion, but the savage natives of certain tropical countries had the same idea. Koch tells us that certain natives of German East Africa who lived in a mountainous, and therefore non-malarial, part noticed that when they descended to the malarial regions on the coast they acquired a fever which they called mibu.' They said that they were bitten there by certain insects which they also called 'mbu'—mosquito or gnat. They give the same name to the mosquito and to the fever, therefore obviously these savages associate the insect and the fever as cause and effect. Peasants in certain parts of Italy have the same idea, believing that the bite of the mosquito may be followed by the development of malarial fever.

Laveran, some years ago, in one of his numerous works on malarial fever, said that possibly the malarial parasite was cared for by the mosquito in the same way that the latter cares for the filaria of the blood. He did not, however, formulate a definite theory on the subject.

In 1894 I was engaged in working at malaria, following out Golgi's work and that of other Italians. I was particularly struck by the phenomena of exflagellation and more particularly by the fact that it