Our success with the simultaneous inoculation of a patient with both Plasmodium vivax and P. falciparum by means of a lot of Anopheles quadrimaculatus simultaneously infected with both species of parasites (1) led us to extend our observations in a direction calculated to give a better idea of the infecting potentialities of such multiply infected mosquitoes. We undertook the multiple infection of several lots of mosquitoes under conditions that would provide: (a) One lot (547) maturing the vivax infection first; (b) One lot (551) maturing the falciparum infection first; and (c) One lot (550) in which both infections would mature simultaneously.
These infections were accomplished by applying the mosquitoes successively to patients separately harboring P. vivax and P. falciparum respectively. After the infective feedings all lots were incubated at a temperature varying from 20° to 23°C. The details of the manner in which the several lots were infected are presented in table 1, which also shows the degree of infection secured in several companion lots employed as controls.