The Great Influenza Read Online Free

advocated precise observation, then theorizing. As the texts stated, 'For a theory is a composite memory of things apprehended with sense perception.' 'But conclusions which are merely verbal cannot bear fruit.' 'I approve of theorizing also if it lays its foundation in incident, and deduces its conclusion in accordance with phenomena.'
    But if such an approach sounds like that of a modern investigator, a modern scientist, it lacked two singularly important elements.
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    First, Hippocrates and his associates merely observed nature. They did not probe it.
    This failure to probe nature was to some extent understandable. To dissect a human body then was inconceivable. But the authors of the Hippocratic texts did not test their conclusions and theories. A theory must make a prediction to be useful or scientific (ultimately it must say, If this, then that ) and testing that prediction is the single most important element of modern methodology. Once that prediction is tested, it must advance another one for testing. It can never stand still.
    Those who wrote the Hippocratic texts, however, observed passively and reasoned actively. Their careful observations noted mucus discharges, menstrual bleeding, watery evacuations in dysentery, and they very likely observed blood left to stand, which over time separates into several layers, one nearly clear, one of somewhat yellowy serum, one of darker blood. Based on these observations, they hypothesized that there were four kinds of bodily fluids, or 'humours': blood, phlegm, bile, and black bile. (This terminology survives today in the phrase 'humoral immunity,' which refers to elements of the immune system, such as antibodies, that circulate in the blood.)
    This hypothesis made sense, comported with observations, and could explain many symptoms. It explained, for example, that coughs were caused by the flow of phlegm to the chest. Observations of people coughing up phlegm certainly supported this conclusion.
    In a far broader sense, the hypothesis also conformed to the ways in which the Greeks saw nature: they observed four seasons, four aspects of the environment (cold, hot, wet, and dry) and four elements (earth, air, fire, and water.)
    Medicine waited six hundred years for the next major advance, for Galen, but Galen did not break from these teachings; he systematized them, perfected them. Galen claimed, 'I have done as much for medicine as Trajan did for the Roman Empire when he built the bridges and roads through Italy. It is I, and I alone, who have revealed the true path of medicine. It must be admitted that Hippocrates already staked out this path' . He prepared the way, but I have made it possible.'
    Galen did not simply observe passively. He dissected animals and, although he did not perform autopsies on humans, served as a physician to gladiators whose wounds allowed him to see deep beneath the skin. Thus his anatomic knowledge went far beyond that of any known predecessor. But he remained chiefly a theoretician, a logician; he imposed order on the Hippocratic body of work, reconciling conflicts, reasoning so clearly that, if one accepted his premises, his conclusions seemed inevitable. He made the humoral theory perfectly logical, and even elegant. As historian Vivian Nutton notes, he raised the theory to a truly conceptual level, separating the humours from direct correlation with bodily fluids and making them invisible entities 'recognizable only by logic.'
    Galen's works were translated into Arabic and underlay both Western and Islamic medicine for nearly fifteen hundred years before facing any significant challenge. Like the Hippocratic writers, Galen believed that illness was essentially the result of an imbalance in the body. He also thought that balance could be restored by intervention; a physician thus could treat a disease successfully. If there was a poison in the body, then the poison could be removed by evacuation. Sweating, urinating, defecating, and vomiting