Paris, G. Masson, 1878. 8°, 23, (1) pages ; original wrappers (spine fragile with small losses of paper). Rare offprint inscribed by Chamberland to the French chemist Louis Joseph Troost : « A mon maître M. L. Troost. hommage affectueux. Ch. Chamberland ». « In this speech Pasteur first introduced the term germ theory and defined its applications in medicine, surgery, and infectious disease. The speech was first published in condensed form in Comptes rendus. de l'Académie des Sciences, 86 (1878) 1037-1043. For that version authorship was expressed as Pasteur, Joubert et Chamberland. » (G&M 14194). « In this important lecture to Paris' Académie de Médecine, Pasteur presented some early and key concepts of bacteriology which were instrumental in the evolution of asepsis. Pasteur discussed the existence of anaerobic and aerobic organisms, defined what later proved to be bacterial toxins, differentiated between virulent and avirulent bacteria, considered specificity of bacteria, superinfection, interference, as well as bacterial antagonism and protagonism. In addition, he stressed the importance of the role of germs in infections and emphasized the need for proper antiseptic and sterilization procedures in order to avoid the chance of infection. » (Heirs of Hippocrates 1899). In original condition.