49^ Malaria 



nicious, are rapidly fatal, others develop into a chronic cachexia, 

 with profound anemia and complete incapacitation for physical 

 or. mental effort. The discovery of Peruvian or Jesuits' bark, and 

 its introduction into Europe by the Countess del Cinchon, the wife 

 of the Viceroy of Peru, about 1639, marked an important epoch in 

 the study of malarial fever. The isolation of its alkaloids, quinin 

 and cinchona, begun in 1810 by Gomez and perfected in 1820 by 

 Pelletier and Coven tou, a second great epoch. But the most im- 

 portant epoch began in 1880, when Charles Louis Alphonse Laveran,* 

 a French physician engaged in the study of malarial fever in Algeria, 

 announced the discovery of a parasite, to which he gave the name 

 Plasmodium malarias, in the blood of patients suffering from the 

 disease. His observations were immediately confirmed, Butschh 

 recognizing the parasitic nature of the bodies observed. For the 

 discovery he was awarded the Breant prize. 



Laveran, however, threw no light upon the source of infection, and 

 malaria continued to be described as a miasmatic disease. 



It was, however, recognized that there were different types of 

 parasites corresponding to the different clinical forms of the disease, 

 and Golgif succeeded in correlating the various appearances of the 

 parasites so as to express their life cycles. But in spite of the in- 

 teresting and important work of Golgi, Celli, Bignami and Marchia- 

 fava, and many others, no progress was made in accounting for the 

 entrance of the parasites into the human body. 



This problem had long interested Sir Patrick Manson, who had 

 devised a theory which, though wrong, in detail, proved in the end to 

 open the door to the next important discovery. Finding that the 

 malarial parasites could not be shown to leave the body in any of 

 its eliminations, and remembering that the same was true of the 

 filarial worms and their embryos, Manson came to the conclusion 

 that they must be taken out of the blood by some suctorial insect. 

 The one naturally first considered was the mosquito, which was 

 known to abound wherever malaria prevailed. Examining mos- 

 quitoes that had been permitted to distend themselves with the 

 blood containing the parasites, Manson found that in the stomach 

 of the insect the peculiar phenomenon known as "flagellation," 

 long before observed by Laveran, took place in the parasites, giving 

 rise to long, slender, lashing, and, finally, free-swimming filaments. 

 These, he conjectured, might be the form in which the parasites 

 left the mosquito to infect the swamp water, with which human in- 

 fection eventually was brought about. Here Manson failed, but 

 while he was investigating he explained the whole matter to Major 

 Ronald Ross, who was soon to go to India, and whom he advised to 

 make the matter a subject for study when he arrived at his destina- 

 tion. Rossi accepted the opportunity that soon presented itself, 



* "Acad. d. M6d.," Paris, Nov. 28 and Dec. 28, 1880. 

 t "R. Accad. di Medicina di Torino," 1885, xi, 20. 

 i "Indian Medical Gazette," xxxm, 14, 133, 401, 448. 



