Somewhere in all this, it was thought, there also resided a mysterious elan vital, the force that brought inanimate objects to life. No-one knew where this ethereal essence lay, but two things seemed probable: that you could enliven it with a jolt of electricity (a notion Mary Shelley exploited to full effect in her novel Frankenstein); and that it existed in some substances but not others, which is why we ended up with two branches of chemistry4: organic (for those substances that were thought to have it) and inorganic (for those that did not).