Penicillin

Abstract

The story of the discovery of penicillin by Alexander Fleming is by now so well known that nothing beyond the bare outlines need be recounted here. Fleming was a dour, reticent, patient, tireless and highly perceptive bacteriologist who, after qualifying in medicine, joined a research group under Sir Almroth Wright at St. Mary’s Hospital, where new ideas in vaccine therapy were being enthusiastically pursued. His experiences as a doctor in the First World War had heightened his distrust of the value of the chemical antiseptics, at that time in common use, and had strengthened his belief in the power of the natural protective mechanisms of the human body. In 1922 he discovered that a substance, which he named lysozyme, found in numerous secretions and tissues of the body, had an extraordinary power of destroying some bacteria without injuring cell tissue: a classic instance of a discovery coming to a prepared mind. In 1928, when Fleming had become Professor of Bacteriology in the University of London, the acute observation of a chance occurrence led him to the discovery of penicillin. When the cover of one of the plates on which he was cultivating bacteria was momentarily removed, a spore of the mould Penicillium notatum settled on the plate and Fleming noticed that, around the mould, bacteria were being destroyed. His interest immediately excited, he went on to find that penicillin was neither toxic to animals nor to the white corpuscles. He recognised its vast potential value as an antiseptic; he drew up a list of those bacteria attacked by it and those which remained unaffected. His find-ings have not since been significantly altered. Although there are many experts who believe that Fleming’s contribution to the final, successful use of penicillin has been exaggerated, his fame for the original and pregnant observation seems to be securely established.