Word: bacteria
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Dates: during 1940-1949
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...discovery of penicillin (almost by accident) in 1928 was a conspicuous breakthrough. Britain's Dr. Alexander Fleming noticed that the mold Penicillium notatum secretes a substance that kills certain bacteria growing on culture dishes. Later it was found that the secretion also kills many disease-producing organisms in the human body. It also does its job without any appreciable damage to human tissues. Fleming's great discovery focused attention on the fact that some micro-organisms are powerful chemical weapons that can be used against other disease-causing microorganisms...
...Every place that is favorable for the growth of micro-organisms (and most places are) is a churning battleground of small, fierce creatures. A pinch of moist soil weighing one gram, for instance, may contain more bacteria (up to 2 billion) than there are people on earth. Among the ordinary creatures prowl savage protozoa engulfing them one by one. There is an underworld, too, made up of submicroscopic viruses, hardly more than big molecules, which often invade the larger organisms and multiply explosively...
Dubos took samples from patches of soil and noted which micro-organisms were present in them and how many of each kind. Then he made a brew of pneumonia bacteria and poured it on material from the patches. He repeated the experiment many times, watching for changes in the soil's microscopic population. Some of the organisms thrived on the strange diet, indicating that they might destroy pneumonia bacteria. Dubos made cultures of the hardy fighters and tested them against various disease-causing organisms...
...this method and refinements of it, he at last found, in a sample of cranberry bog soil sent to him by Waksman, an organism from whose cultures he separated an active fraction that he named gramicidin. It killed or halted many disease bacteria, but it was dangerous for internal...
Doctors are keenly aware that the antibiotics (sulfa drugs, penicillin, streptomycin, etc.) have two great dangers: 1) sometimes the drug has a poisonous effect on the patient, and 2) the bacteria under attack may develop a tolerance for the drug. Last week doctors at the 13th Congress of the International Society of Surgery in New Orleans were reminded of another danger: antibiotics speed up the clotting time of the blood, thus subject the patient to the risk of death from blood clots forming, breaking loose, and being carried through the heart into the lungs...