THE MOSQUITO FISH (GAMBUSIA) AND ITS RELATION 
TO MALARIA 
By Davin Starr JORDAN 
[With 4 plates] 
One of the most important discoveries of the nineteenth century 
was that of the nature of malaria, with its kindred diseases, yellow 
fever, dengue, and the like. It has been found that malaria is not 
a product of miasma or foul air, as the accepted name of “bad air” 
would signify. Neither is it “catching” in the ordinary sense of 
propagation by contact. It is borne from one person to another 
by the bite of mosquitoes. The big mosquitoes of the North (Culicita 
and the like) may offend by their abundance, their vociferous song, 
and their vicious bite, but they do not carry disease. The dangerous 
ones are smaller, less insistent, and with a softer voice, but some 
of them transmit active and dangerous poisons. 
The cause of malaria of all sorts, ague, chills, and fever, 
mittent ” and “ intermittent fever,” as well as of the more vicious 
“Roman fever” and dengue or “ break-bone fever,” and the most 
virulent of all, the yellow fever, is the presence in the blood of multi- 
tudes of minute, parasitic animals, wormlike in form, which at 
intervals breed in prodigious numbers, with varied degrees of danger 
or discomfort. The biting of a man having malarial trouble by 
a mosquito of certain kinds (Anopheles, ddes, and Stegomiya) 
transfers one or dozens of these creatures to its own body, causing 
it, no doubt, lamentable discomfort. Later the mosquito may bite 
another person “to take the taste out of his mouth,” and in this 
next victim fever follows, thus passing the malady along from 
person to person through the agency of the mosquito’s body. It is 
said that in most species only the female bites and that she does so 
chiefly after drawing blood. 
The problem of the cure of malaria rests primarily on our skill 
in poisoning the malarial parasite with the least damage to their 
human host. Thus far the most successful method has been the 
use of salts of quinine. This is extracted from Peruvian bark de- 
rived from the tree, Cinchona calisaya, and numerous other species of 
Cinchona and Feinija and is fatal to all malarial microbes with 
which it comes in contact. Quinine is not a very wholesome drug as 
far as man is concerned though used under numerous conditions. 
The main point is that it kills microbes without killing the patient. 
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