[AND IT WAS NAMED PENICILLIN-CRUSTOSIN VIEM].

The article, on the basis of analysis of declassified archival documents and published sources, reveals the circumstances of identification of the strain that served as producer of the first National preparation of penicillin, named Crustozin. It is established that, since the middle of 1940s, among scientists circulated opinion about its specific affinity that differed from the one officially accepted in the USSR. The existing situation forced Professor L. I. Kursanov to take measures to protect his scientific reputation. The mode of action he choose permitted him to prove his professional competence without destroying the formed postulate.