By dozens of brilliant experiments of this kind, Metchnikoff forced his opponents to admit that phagocytes, sometimes, can eat vicious microbes. But the pitiful waste of this brainy Metchnikoff’s life was that he was always doing experiments to defend an idea, and not to find the hidden truths of nature. His experiments were weird, they were often fantastically entertaining, but they were so artificial--they were so far away from the point of what it is that makes us immune. You would think that his brain, which seemed to be able to hold all knowledge, would have dreamed of subtle tests to find out just how it is that one child can be exposed to consumption and never get it, while some carefully and hygienically raised young girl dies from consumption at twenty. _There_ is the riddle of immunity (and it is still completely a riddle!). “Oh! it is doubtless due to the fact that her phagocytes are not working!” Metchnikoff would have exclaimed, and then he might rush off to flabbergast some opponent by proving that the phagocytes of an alligator eat up typhoid fever bacilli--which never bother alligators anyway. The devotion of the workers in his laboratory was amazing. They let him feed them virulent cholera bacilli (even one of those pretty inspirational girls swallowed them!) to prove that the blood has nothing to do with our immunity to cholera. For years--he himself said that it was an insanity of his--he was fond of toying with the lives of his researching slaves, and the only thing that excused him was his perfect readiness to risk death along with them. He swallowed more tubes of cholera bacilli than any of them. In the midst of this dangerous business, one of the assistants, Jupille, became violently sick with real Asiatic cholera and Metchnikoff’s remorse was immoderate. “I shall never survive the death of Jupille!” he moaned, and Olga, that good wife, had to be on her guard day and night to keep her famous husband from one of his (always fruitless) attempts at suicide. At the end of these strange experiments, Metchnikoff jabbed needles into the arms of the survivors, drew blood from them, and triumphantly found that this blood did not protect guinea-pigs from doses of virulent cholera germs. How he hated the idea of blood having any importance! “Human cholera gives us another example,” he wrote, “of a malady whose cure cannot be explained by the preventive properties of the blood.”