. Applied bacteriology for nurses. todirect attention also to suppressing the mosquitonuisance, and, hand in hand with that, to kill the malarialparasites in their human hosts by means of quinin. Mosquitoes It may be well at this point to give a brief outline of thelife-history of mosquitoes, especially those concerned inthe transmission of malaria and of yellow fever. Mosquitoes reproduce themselves by means of eggswhich the female lays on the surface of stagnant several days the eggs hatch out into what are calledwrigglers, which live in the water and can readily beseen with the
. Applied bacteriology for nurses. todirect attention also to suppressing the mosquitonuisance, and, hand in hand with that, to kill the malarialparasites in their human hosts by means of quinin. Mosquitoes It may be well at this point to give a brief outline of thelife-history of mosquitoes, especially those concerned inthe transmission of malaria and of yellow fever. Mosquitoes reproduce themselves by means of eggswhich the female lays on the surface of stagnant several days the eggs hatch out into what are calledwrigglers, which live in the water and can readily beseen with the naked eye. After a day or two the wrigglerchanges into a pupa, and from this, after a further inter-val, the winged insect, the mosquito, emerges. It is MALARIA 131 thus seen that stagnant water is necessary for mosquitoesto breed. Both wrigglers and pupae come to the surfaceof the water at brief intervals in order to breathe. If afilm of oil is floated on the surface of the water the wrig-glers and pupae soon die of Fig. 42.—Life cycle of mosquito. Chart showing how the com-mon house mosquito breeds: 1, The eggs, as deposited on the sur-face of the water; 2, separating from the mass. The larva, 3, 4,forming; 5, emerging, about the thickness of a thread; 6, breath-ing through the tail; 7, changing to pupa. The pupa (8, descend-ing from the surface, when disturbed; 9, 10, breathing; 11, 12,changing to insect). The complete insect (13, emerging; 14,allowing its wings and body to harden and expand ready for flight,using the pupal skin, 15, as a float). The eggs and young of themalaria-carrying mosquitoes go through a similar process of devel-opment. The mosquitoes which transmit malaria belong to thefamily called Anopheles. The commonest variety of thisis broT\Ti in color and has four dark brown markings oneach wing. Anopheles mosquitoes breed in fresh-waterswamps and in stagnant water in fields and woods. Theirextermination therefore requires the drainage of mars
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbacteri, bookyear1919
