DAHLGREN, THE MALARIA MOSQUITO 



39 



mosquitoes remain. This disappearance of malaria may have been 



brought about by a general use of quinine. Quinine, obtained from 



various species of trees of the genus Cinchona, growing at high altitudes 



particularly on the Andes and brought into use in Europe in 



the year 1640 by the Countess Chinchon, vice-queen of Peru, quinine 



who had been cured of malaria by its use, is the only known 



specific against malaria. It will, if properly administered, destroy the 



parasites of tertian and quartan fever in a comparatively short time. 



The parasite of tropical fever, however, such as exists in its severest 



form in certain places on the West Coast of Africa, on the southernmost 



FIG. 32. THE MALARIAL SPORES IN THE MOSQUITO 



C. A sporocyst with contained spores (X 400) (after Grassi). S. The 

 liberated spores (X 3000). G. Section of the salivary gland of the mosquito, 

 malarial spores lying in the cells and in the duct of the gland, (X 350) (after 

 Grassi). 



of the Philippine Islands and in the Malay Archipelago, is only slightly 

 affected even by quinine, after the parasite has once begun to multiply 

 in the blood. The sexual forms of the malarial organism are especially 

 resistant and may, long after the destruction of all asexual parasites, 

 take the place of these latter and by simple division give rise to new 

 crops of spores. As a preventive the drug has, however, been found 

 highly serviceable by those obliged to travel or to live in tropical 

 malarial countries. 



As an example of a local malarial epidemic may be mentioned an out- 

 break, described by Dr. W. X. Berkeley, which took place near Jerome 



