It has been shown by Lawrow and Dubowskoj1(1937), by Berberian2(1939), by Senekji and Beattie3(1941) and by Katzenellenbogen4(1942) that lasting immunity against oriental sore can be induced artificially by inoculating susceptible human beings intracutaneously with suspensions of living cultures of Leishmania tropica in isotonic solution of sodium chloride as well as with infective material obtained from early sores on patients. The present paper discusses attempts to induce immunity by the use of a killed vaccine. During 1938 and 1939 I used as vaccine a phenolized suspension of leishmanias. Freshly isolated local strains of tropica grown on a modified N. N. N. medium were used. The cultures varied from six to eight day old primary cultures to fifty day old fourth generation subcultures. The leishmanias were suspended in 0.5 per cent phenolized saline solution. This concentration of phenol