The opportunity afforded by the acquirement of a strain of Plasmodium falciparum, evidently derived from the Republic of Panama, suggested the desirability of extending the studies on relative susceptibility already reported (1, 2).
The history of the patient from whom the strain was secured is as follows:
The patient, a white male aged 45, a forester by occupation, had been a resident of Pensacola, Florida, for the year prior to the events described. To his recollection he had never previously experienced any unexplained febrile illness, nor prior to the trip discussed, had ever been in the tropics. He left Pensacola by plane on March 28, 1938, for the Canal Zone, arriving March 30. A few days later he left on a trip to inspect timberlands in the interior of the Republic of Panama, in the course of which he was at the town of David on April 5, but did not spend the night at that place.