Blood Read Online Free Page A

acquired a certain personality or chemical balance, it gets thrown into turmoil and must regain equilibrium. It can manage stress, but only so much. I imagine blood as the planet earth, and all of the bodily reactions to disturbances — be they sugar or alcohol — as gravitational forces, pulling everything back to the ground. You’re in trouble when your gravitational forces don’t work, or when you’ve overdone it so much that your body just can’t cope. That, by my way of thinking, is like shooting a rocket through space with no way of bringing it back down to earth.
    Travelling like an indefatigable river along its intertwined circulatory systems, passing through the heart and lungs and feeding the rest of the body, blood keeps us alive and has forever held us in its debt. To it we owe our daily health. To it we pay ransom — insulin injections, chemotherapy treatments, bone marrow transplants, the use of clotting factors — when order turns to disorder in our arteries and veins. And from it we build a frame to envisage our own humanity. We let it run from our veins as a gift to others in failing health. And if we believe in a superior being, we give it up as an offering so that we may go on living.
    WHAT WE NOW KNOW about blood seems all the more astounding when we think about where we have come from. For some two thousand years, philosophers and physicians imagined blood as one of the fundamental characteristics of our body and soul. We linked it to the spring, the air, and the liver.
    Thanks to the theories of figures such as Hippocrates, in 460 BCE , and Galen, in about 200 CE , we came to believe that sickness arose as a result of disequilibrium between four key parts (or humours) of the body: blood, yellow bile, black bile, and phlegm. Hippocrates inspired the Hippocratic oath and is often referred to as the father of modern medicine. Claudius Galen proved the presence of blood in the arteries, and argued that arteries and veins are distinct and that the liver has a key role in blood production. “The liver is the source of the veins and the principal instrument of sanguification,” Galen wrote in On the Usefulness of the Parts of the Body .
    Galen argued that the preponderance of one particular humour went so far as to determine a person’s basic personality type. One might be sanguine, choleric, bilious, or melancholic — words and concepts that continue to resonate with us today. Blood, for example, was said to quicken the spirit, and the adjective “sanguine” derives from the old French word sanguin and from the Latin sanguineus (meaning “of blood”). It refers to a person who is courageous, loving, and optimistic, especially in difficult situations. The New Oxford American Dictionary offers the following definition of “sanguine” in the context of medieval science and medicine: “of or having the constitution associated with the predominance of blood among the bodily humours, supposedly marked by a ruddy complexion and an optimistic disposition.”
    But too much of any humour would create a dangerous disequilibrium in both temperament and health — the elusive “mind-body” balance we still search and long for today. Traditional Islamic medicine and the Ayurveda medicine of ancient India suggest food and diet as one means to correct imbalances of the humours.
    Another was the technique of bloodletting, or phleb­otomy. In retrospect, it is sobering to imagine how many thousands of patients have died from bloodletting or its complications. I, for one, hate having my blood played with or withdrawn and feel grateful in the extreme for Louis Pasteur and Robert Koch, both nineteenth-century scientists who demonstrated that inflammation results from infection, thus obviating any need for bloodletting.
    Bloodletting is still practised in a few ways. We donate blood, have it withdrawn for laboratory tests, and use it to treat