Page:Tropical Diseases.djvu/749

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TRANSMISSION
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infected, and after many meals of banana, they could still be found coiled up in the head or stretched out in the labium. Probably heat and moisture play a part in this respect, as has been shown to be the case by Fülleborn.

Fig. 107.—F. bancrofti in head and proboscis of mosquito.

a, a, a, Filariæ; b, labium; c, labrum; d, base of hypopharynx; e, duct of veneno-salivary gland; f, f, cephalic ganglia; g, g, eye; h, œsophagus; i, pharyngeal muscle.

These observations prove that, like the malaria parasite, the filaria is introduced into its human

    solution, and placed them on the stage of the microscope. He separated the various parts of the proboscis by a slight pressure so as to observe more clearly, and placed the flame of a Bunsen burner close to the slide. He noticed that the filariæ moved violently within the labium when the liquid in which the mosquito was bathed attained a higher temperature. Finally, one managed to pierce its way through at the tip of the labium, and was soon followed by others. He noticed the escape of five filariæ within a minute. Sometimes two passed simultaneously. Too high a temperature killed both larvæ and mosquito. A fall of temperature arrested the process.