THE SELECTIVE ACTION OF THIOBISMOL ON INDUCED MALARIA

One of the problems of the malarial therapy of neurosyphilis has been the need of a drug to reduce the frequency of the paroxysms without eliminating them altogether. Until recently no drug, including the common antimalarials, has demonstrated a reliable selective effect, the administration of the drug causing either no change or a total suppression of the paroxysms. In 1939 Schwartz 1 found that thiobismol (sodium bismuth thioglycollate) would convert Plasmodium vivax paroxysms from a quotidian (daily) periodicity to a tertian (alternate days) periodicity. Subsequently other workers 2 confirmed this observation. However, the age (measured in the number of hours from the last fever peak) at which parasites are affected and therefore the best time to administer the drug have not been definitely established. The present investigation was undertaken with a twofold purpose: (1) to determine at what age the parasites are affected by thiobismol and consequently the optimum time