WHETHER life processes obey the second law of thermodynamics or if life finds a way of evading the otherwise universal dissipation of energy has been something of a puzzle for a century. Kelvin left the matter open in his formulation of the Second Law, by expressly excluding the operations of ‘animate agencies’. Since then, opinions on both sides have been expressed, although a majority would probably be found in favour of the view that any local increase of ‘free’ energy is compensated by a greater amount of dissipation elsewhere, or as Schrodinger has recently put it1 in picturesque if somewhat inaccurate language, the organism feeds on ‘negative entropy’. On the other hand, G. N. Lewis2 referred to living organisms as “cheats in the game of entropy”, which “alone seem able to breast the great stream of apparently irreversible processes. These processes tear down, living things build up. While the rest of the world seems to move towards a dead level of uniformity, the living organism is evolving new substances and more and more intricate forms.”