Now it is surely evident on consideration, though the significance of the change has been ignored, that the whole discussion of the spontaneous origin or evolution of life in matter takes an entirely new shape when our old and widely erroneous conception of matter is abandoned, and a true one is substituted. Life is a marvellous and characteristic demonstration of energy. When the origin of this energy in matter was formerly discussed, we were told that the constituent parts of matter contain no energy at all, but now we know that a quite overwhelming proportion of the sum total of universal energy is to be found there, and nowhere else. This is one of the most revolutionary advances in the whole history of thought, and its full significance has yet to be recognised. There must also be added an essential to any future discussion of this question, the extraordinary achievement of synthetic chemistry, of which Professor Berthelot was the grand master. As long ago as 1828 it was shown that there was at least one exception to the doctrine of the vitalists, that chemical compounds characteristic of living matter cannot be built up except by the living organism. To-day chemistry has succeeded in building up alcohols, starches, sugars, and even the forerunners of the proteids themselves, from the inorganic elements in the laboratory, under the action of non-vital forces. This fact could not be reckoned with a generation ago. [Sidenote: Can Chemistry Build Up Life?] We are now entitled to state very briefly the sequence of events which may reasonably be imagined as culminating in the origin of life upon the earth _for the first time_. Whatever we may hold as to the present, we have to recognise that the origin of life for the first time constituted a fact utterly different in certain essentials from any origin of life that may be expected to be occurring to-day. The capital fact is that in the beginning there was no organic matter to serve as food material. If ever there was a case in which it is the first step that costs, it is here. Nothing can be easier than to imagine the spontaneous origin of life in organic matter to-day, favoured with sun and water and air. The case is far different when a primary origin in inorganic matter has to be conceived. But of some things we are certain. We are certain, for instance, that so long as the earth’s surface temperature was above that of boiling water, no life was possible. It was not until the gaseous water in the atmosphere became liquefied by the lowering of the earth’s temperature that the production of life became possible. The first seas were seas of boiling water, or rather water infinitesimally below the boiling point, and we may reasonably suppose, with Buffon, that the Polar seas, being the first to cool, must have provided the first “nest” for life upon the earth. I assume, of course, that this essay will be read in conjunction with that of Professor Sollas upon the formation of the