Once the cells in a biological machine stop working, it can never be started again. It goes into a cascade of decay, falling toward disorder and randomness. Except in the case of viruses. They can turn off and go dead. Then, if they come in contact with a living system, they switch on and multiply.

The Hot Zone: The Terrifying True Story of the Origins of the Ebola Virus (ed. Anchor, 2012) - ISBN: 9780307817655