Microbe Hunters, Bright Side and Dark Side, Part I

 

Microbe Hunters was the title of a wonderfully successful science-popularzing book written by Paul de Kruif and published by Simon & Schuster in 1926. 

The book is on its face a set of capsule biographies of prominent biologists from Leeuwenhook to Paul Ehrlich. Leeuwenhook invented the microscope: Ehrlich found a cure for syphilis in 1909. 

But de Kruif had an underlying organizing principle by which he made his selection. The book was about the pragmatic successes of the germ theory of disease. Specifically, a 'typical' disease has one cause, and the cause is usually a germ. The way to cure (or immunize people from) a disease is to find the germ that causes it, then either(a) find a way to kill that microbe without doing damage to the surrounding tissue (a "magic bullet" as Ehrlich called such a discovery) or find a way to assist the body's own immune system in doing the same. Hence, the title of the book. 

The only character in the book to get two chapters is Louis Pasteur. That happens because (like Grover Cleveland among American Presidents) Pasteur appears in two distinct capacities. In his early career he help destroy the idea of "spontaneous generation." One of de Kruif's key points is that the destruction of the idea of spontaneous generation was critical to the development of the germ theory. Our tiny biological enemies are not spontaneously generated within our bodies -- they must come into it from outside.  

The de Kruif cuts away from Pasteur and has a chapter for Robert Koch, the German bacteriologist who identified the microbe  responsible for anthrax. The work made Koch world famous, and eventually resulted in his receipt of a new invention called the Nobel Prize in Medicine. As de Kruif tells the story, this made Koch the world's most prominent "microbe hunter," a distinction that annoyed Pasteur, who had also been working on anthrax. So Pasteur, like Cleveland, took the title back, by his work on a rabies vaccine in the 1880s.  

Microbe Hunters is an excitingly written book that creates much of its effect by giving us only one side of the story, what we might call its bright side. These are guys who were right, who pursued and in some way advanced the germ theory. But the germ theory isn't always the answer. Consider cancer. It is generally now understood that here is no cancer germ or virus. The causation of cancer is still an imperfectly understood matter, but there is likely a genetic disposition, in many cases, and many inorganic triggers such as tobacco smoke or even excessive exposure to sunlight, and there are lifestyle risks such as obesity. 

Part of the dark side of the microbial or germ theory of disease may be that it has sometimes created a wild goose chase, sending scientists off in the wrong direction. Exactly that did happen within the history of cancer research, and I'll discuss it some more tomorrow.