The Boundary of Life

The harder we look at the border between life and non-life, the more elusive does the distinction become. Life, the animate, was supposed to have some sort of vibrant, throbbing quality, some vital essence - made to sound yet more mysterious when dropped into French: elan vital. Life, it seemed, was made of a special living substance, a witch's brew called 'protoplasm'. Conan Doyle's Professor Challenger, a fictional character even more preposterous than Sherlock Holmes, discovered that the ...