This seems a complete demonstration of the passage of the organic into the inorganic world in the way of analysis, or taking the puzzle to pieces. In the opposite way of synthesis, or putting it together, the nearest approach yet made has been in the manufacture of those organic compounds already referred to, such as urea, alizarine, indigotine and other products which had hitherto only been known as products of animal or vegetable life. Of these a vast number have been already formed from inorganic elements by chemical processes, and almost every day announces some fresh discovery. Under these circumstances it is unsafe to affirm either, on the one hand, that the problem has been solved and that life has ever been made in a laboratory; or, on the other hand, that there is any such great gulf fixed between the organic and the inorganic, that we can assume a break requiring secondary supernatural interference to surmount it, and ignore the good old maxim that ‘Natura nihil facit per saltum.’ Positive proof is wanting, but the probabilities point here, as they do everywhere else throughout the universe, to the truth of the theory of ‘original impress’ as opposed to that of ‘secondary interference.’ It remains to show how the fundamental law of polarity affects the more complex relations of life and of its various combinations. And here it is important to bear in mind that as the factors of the problem become more intricate and complex, so also do the laws which regulate their existence and action. Polarity is no longer a simple question of attraction and repulsion at the two ends of a magnet or at the opposite poles of an atom. It appears rather as a general law under which as the simple and absolute becomes differentiated by evolution into the complex and manifold, it does so under the condition of developing contrasts. For every _plus_ there is a _minus_, for every like an unlike; one cannot exist without the other; and, although apparently antagonistic, harmonious order is only possible by their co-existence and mutual balance.