Now, many of the properties of inorganic colloids approximate those found in living structures, which appear to be "alive" by reason of the conversion of the energy of the sunlight into the chemical energy of their constituent (organic) colloids. The agent in this conversion is the green substance chlorophyll in the cell or cells of the plant; and, directly or indirectly, all the energy in living things arises from this one source, transmuted by this one transformer. Yet chlorophyll is far too complex a substance to arise as a first step from inorganic matter, even where conditions are suitable for life to appear; and the spontaneous production of such a thing as a bacterium would not solve the problem, for the new-born cell would have no organic food, and must at once perish. In an utterly lifeless planet inorganic colloids must first develop, and in time one of these must begin to evolve not a living cell, or anything so complex as a bacillus, but something in the way of a molecule holding a higher store of chemical energy than anything before it. Later such colloids, perhaps uniting with others, would begin to condense and form more complex organic molecules, and finally effect unions with crystalloids. Thus would organic complexity gradually be led up to, chlorophyll brought into being, and life appear. One of the foremost of the biochemists, Prof. Benjamin Moore, of the University of Liverpool, has summed this up picturesquely: "It was no fortuitous combination of chances, and no cosmic dust, which brought life to the womb of our ancient Mother Earth in the far-distant Paleozoic ages, but a well-regulated orderly development, which comes to every mother earth in the universe in the maturity of her creation when the conditions arrive within the suitable limits. Given the presence of matter and energy forms under the proper conditions, life must come inevitably.... If this view be the true one, there must exist a whole world of living creatures which the microscope has never shown us, leading up to bacteria and the protozoa. The brink of life lies ... away down among the colloids, and the beginning of life was not a fortuitous event occurring millions of years ago and never again repeated, but one which in its primordial stages keeps on repeating itself all the time and in our generation. So that, if all intelligent creatures were by some holocaust destroyed, up out of the depths in process of millions of years intelligent beings would once more emerge."