Continuing the thought from yesterday ... my recent reading includes MALIGNANT GROWTH, a work by Alan Marcus, which is specifically devoted to the dark side of the "microbe hunting" paradigm in medical research. What happens if one diligently pursues the microbe that isn't there? In 1887, a Dr Robert Morris wrote in POPULAR SCIENCE MONTHLY, "It seems more than probable that all malignant growths belong to the infectious microbic diseases, and that by to-morrow we shall have the tiny causators." That phrase, "malignant growth" as a synonym for cancer tumors, the defining characteristic of the disease, gave Marcus his title. The line also seems, more than any other datum, to have inspired his thesis: that from Morris' time until the First World War, scientists all over the world sought to understand and cure cancer by chasing a phantom, the non-existent cancer microbe. Further, Marcus contends that many of the institutional structures that we think...