SPECULATIONS ON THE ORIGIN OF DISEASE Classical writers believed that the wind sometimes brought sickness to man, animals, and crops. Hippocrates, the father of medical science, held that men were attacked by epidemic fevers when they inhaled air infected `with such pollutions as are hostile to the human race'. A rival, though perhaps not entirely incompatible, view held that epidemics were the result of supernatural agencies, and were to be warded off or cured by taking appropriate action.
Lucretius in about 55 B.C. held quite modern views. He observed the scintillation of motes on a sunbeam in a darkened room and concluded that their movement must result from bombardment by innumerable, invisible, moving atoms in the air. This brilliant intuition enabled him to account for many interesting phenomena, including the origin of pesti lences. We now know that bodies which transmit human diseases through the air are larger than those which Lucretius thought of as atoms—the mosquitoes carrying malaria, for instance, or the droplets which spread the common cold and influenza viruses indoors. But in his concept of baleful particles carried in clouds by the wind, settling on the wheat or inhaled from the polluted atmosphere, Lucretius touched on some of the main problems existing in plant pathology and allergy today.