In the meantime what may be said as to Huxley’s reservations is this: A considerable step has been made in the direction indicated, by the success of recent chemistry in forming artificially what are called organic compounds, that is, substances which were previously known only as products of animal or vegetable secretions. Urea, for instance, the base of uric acid, with which so many are unfortunately familiar in the form of gout; indigotine, the principle of the blue colouring matter of the indigo plant; and alizarine, that of madder; are all now produced artificially, and have even become important articles of commerce. If chemists can make the indigotine, which the growing plant elaborates at the same time as it elaborates protoplasm, may we not hope some day to make the latter as well as the former product? Now organic compounds of this class are being formed artificially every day, and it is said that chemists have already succeeded in producing several hundreds. But even if this expectation is never fulfilled, we may fall back on Huxley’s second reservation of the enormous difference of chemical and physical conditions in the early stages of the earth’s life from anything now known. It has been calculated that the earth’s temperature when it first started on its career as an independent planet was something like 3,000,000° Fahrenheit. At this heat probably all atoms would be dissociated; but as the temperature diminished they would come closer together, but still with a great deal of motion, and making wide excursions, which might bring many different atoms together in complex though unstable combinations. Moreover, carbon, which is the basis of all such combinations of the class of protoplasm, was far more abundant in those early days in the form of carbonic dioxide gas, before the enormous amount of vegetable matter in the form of coal and otherwise, had been subtracted from it. In any case the first protoplasm must be extremely ancient, for the remains of sea-weeds are found in the oldest strata, and vegetation of any sort implies the manufacture of protoplasm from inorganic matter.