Recently, Major R. N. Chopra, i.m.s., Pro| fessor of Pharmacology at the Calcutta School ; of Tropical Medicine, whilst carrying out some j pharmacological experiments with antimony ; compounds, noticed that when the serum from a kala-azar patient was added to certain of the pentavalent compounds of antimony a heavy precipitate was formed. He found that this precipitate was not formed if normal...