1921

Jan Sicard discovers lipiodol, iodine compound suspended in oil, to be remarkable new contrast agent, initially for spinal region (myelography); introduced in US by Ethel Russell at PGH in 1924 (Kevles, 103-104). Discovery of tomography in France, though first instrument not built until 1931 and, in U.S., in 1937 in St. Louis, where Jean Kieffer’s (French immigrant who worked in X-ray dept. of Conn. TB sanitarium and made his discovery as a patient, not a doctor) version of the tomograph went into production in 1939: “By the fall of 1939, more than a thousand patients had had what they were calling ‘laminagraphs’ in St. Louis” (Kevles, 108-110). Fleming discovers lysozyme, a lytic agent (an enzyme) from mucous and other body secretions (Wainwright, 97-98; Macfarlane, 98-103); lysozyme was bacteriolytic with A. F. coccus (the large, gram-positive coccus, that likely came from air or dust in the laboratory, not from Fleming’s nose). A. F. coccus (M. lysodeikticus) was Fleming’s other discovery: it was the best indicator of lytic activity he and Allison were investigating for the next five years . In his first paper on lysozyme (1922), Fleming showed that 75% of 104 strains of airborne bacteria and other strains of nonpathogenic staphylococci and streptococci were destroyed by lysozyme (Macfarlane, 107). Ernst Chain and Leslie Epstein showed that lysozyme was an enzyme in 1938, but found that the molecule it dissolved was not present in any microbes that caused serious diseases (Lax, 77-78).