QUOTE : Syphilis is caused by a spiral bacterium (aka a spirochete) known as Treponema pallidum. The bacterium is usually acquired during sexual contact, whereupon it corkscrews its way across mucous membranes, multiplies in the blood and lymph nodes, and, if a patient is especially unlucky, gets into the central nervous system, including the brain, causing personality change, psychosis, depression, dementia, and death. That’s in the absence of antibiotic treatment, anyway; modern antibiotics cure syphilis easily. But there were no modern antibiotics in 1917, and the early chemical treatment known as Salvarsan (containing arsenic) didn’t work well against late-stage syphilis in the nervous system. Wagner-Juaregg solved that problem after noting that Treponema pallidum didn’t survive in a test tube at temperatures much above 98.6 degrees Fahrenheit. Raise the blood temperature of the infected person a few degrees, he realized, and you might cook the bacterium to death. So he began inoculating patients with Plasmodium vivax. He would allow them to cycle through three or four spikes of fever, delivering potent if not terminal setbacks to the Treponema, and then dose them with quinine, bringing the plasmodium under control. “The effect was remarkable; the downward progression of late-stage syphilis was stopped,” by one account, from the late Robert S. Desowitz, who was a prominent parasitologist himself as well as a lively writer. “Institutions for malaria therapy rapidly proliferated throughout Europe and the technique was taken up in several centers in the United States. In this way, tens of thousands of syphilitics were saved from a sure and agonizing death”