of science helps us to put such flights of thought in their proper perspective. “One can hardly emerge from such thoughts,” writes Soddy,[2] in pointing out the remarkable adaptation of the human eye to the peculiarities of the Sun’s light, so as to make the best of that wave-length of which there is most, “without an intuition that, in spite of all, the universal Life Principle, which makes the world a teeming hive, may not be at the sport of every physical condition, may not be entirely confined to a temperature between freezing and boiling points, to an oxygen atmosphere, to the most favourably situated planet of a sun at the right degree of incandescence, as we are almost forced by our experience of life to conclude. Possibly the Great Organizer can operate, under conditions where we could not for an instant survive, to produce beings we should not, without a special education, recognize as being alive like ourselves.” It is generally conceded that life on our globe began in the water, and thence spread to the land. Very significant in this regard is the fact that all but the highest plants require the presence of external water for the act of fertilization, as the male cell _swims_ through water to the ovum. Only the most recently evolved groups have shaken off this ancestral trait; and as regards the whole economy of plants the water relation remains, throughout the entire vegetable kingdom, the most obvious and universally important of the different relations existing between plants and their environment. How vegetable life originated, from what inorganic forms it was evolved, is a secret which science has not yet discovered; but since those dim first beginnings it has never been absent from the Earth, so far as we know, and has increased and multiplied, and passed through a thousand changes to higher and higher forms, till it has attained to the beautiful and bountiful and varied plant world which we know, covering with a green mantle most of the land surface of the globe and filling the shallower lakes and seas; while in its minuter forms it swarms in the soils and waters of the Earth, and its germs pervade the atmosphere.