Letter from Howard Walter Florey to Agustin Arriagada, Santiago, Chile Sorry Arriagada was upset at abandonment of name, ayfivin, in favour of bacitracin - not clear that substance Arriagada called subtilin in 1944 is the same as the ayfivin worked on in Oxford - bacitracin was described by Johnson, Anker and Meleny in 1945 - bacitracin is being sold in considerable quantity for local application - bacitracin is, in certain circumstances, used systemically - is being used in animal feeding stuffs - Arriagada's bringing the bacitracin producing strain to Oxford has made it possible for Abraham and Newton to become two of the best polypeptide chemists in the country - interested in Arriagada's suggestions but cannot undertake new line of research at present. 1 July 1954