In this inner order of substance we must see in the very first place the work of the sound or chemical ether. And we should be aware that by the word 'chemistry' in this connexion we mean something much more far-reaching than those chemical reactions which we can bring about by the reciprocal affinity of physical substances, however complicated these reactions may be. A few examples will illustrate the difference between chemical processes caused by direct influence of the chemical ether, and others in which only the physical consequences of the ether are effective. In his book, Man the Unknown, Professor Carrel shows very impressively, by an example from the human organism, the difference of quantitative ratio in externally similar processes, one of which occurs within the domain of life, the other, outside it. He compares the quantity of liquid necessary to keep artificially alive a piece of living tissue which has been reduced to pulp, with the quantity of blood doing the same within the living organism. If all the tissues of a human body were treated in this way, it would take 45,000 gallons of circulating fluid to keep them from being poisoned in a few days by their own waste products. Within the living organism the blood achieves the same task with 1J gallons. Very many chemical changes within living organisms are effected by the two polar processes of oxidation and reduction. We have discussed them repeatedly as hieroglyphs of much that occurs in nature by way of polarity. In accordance with the principle ruling the physical plane of nature, that differences of level tend to disappear, oxidation can occur by itself, whereas reduction requires the expenditure of energy. Let us from this point of view compare the transformation of oxidized into reduced iron, as it takes place inside and outside the realm of life. An example of this process in its purely physical form is the reduction of iron-ore to metallic iron in blast-furnaces, where, with the help of high temperature and high pressure, carbon is made to combine with the oxygen ingredient of the ore and to impart to it its own imponderable energy. Precisely the same process is going on continuously and unobtrusively within the human body under normal bodily conditions of temperature and pressure, when the oxy-haemoglobin of the arterial blood changes over into the haemoglobin of the venous blood. A macrotelluric counterpart of this is the transformation of the red river-mud into the blue-black continental mud at the bottom of the sea, around the continental shores. Here, again, reduction takes place without those preliminaries that are necessary for carrying through the process by technical means.