This great question of how plants came on the earth, and particularly how from these apparently simplest organisms our whole wonderful vegetation has arisen, has always been one of the most interesting things in the history of the world. There are many different ways of studying this, and in the very earliest stages of plant development we are forced to reason, not so much by actual records or buried skeletons of the plants that probably existed then, for only a very few have ever been found, but by our knowledge of the physical and chemical requirements of unicellular plants, and those slightly more developed, and of their individual life histories. It is, for instance, certain that the first plants must have been aquatic, as no real land plants are known for hundreds of thousands of years after the earth was quite capable of maintaining plant life. The absolute necessity of water to complete fertilization in nearly all cryptogams also makes it fairly certain that water plants, and these of the simplest nonflowering type, were the first living things to be found on the earth. And it is more than a fair inference that these were inhabitants of warm or hot water. Subsequently, as the water cooled, they may well have been not unlike the green scum found on ponds to-day. Of course, the actual origin of life itself is still as much of a riddle as it was when the ancient philosophers began to speculate about it years before the Christian era. Protoplasm, the unit or basis of all life, while its composition and growth requirements are fairly well known, has never been made in any laboratory. Nor have scientists ever been able to decide what the combination of physical and chemical forces must have been to originate it. But that from a perfectly sterile, probably steaming hot globe, there did finally develop some form of life, and that this must have been aquatic plant rather than animal life, seems not only certain, but the only hypothesis upon which all subsequent development of life must have been based. It is not necessary to ascribe the origin of life to providential inspiration nor to the meddling of strange and outlandish deities, as all savage tribes did and some more civilized peoples still do. There can, however, be no escaping the fact that life is more than the combination of physical and chemical conditions which sustain it, and that its origin has never, and may never be “explained” by merely describing the conditions which unquestionably favored its appearance. In other words, the origin of plant life throws us back upon things believed but incapable of proof, and is none the less wonderful because we cannot yet understand the probable progression of forces and materials to which it owes its origin.