Page:Popular Science Monthly Volume 50.djvu/514

496 that they had ever lived in any other vicinity, or knew any other materials than the bones and stones and shells of their own valley and its encircling hills. Shut off from communication almost as completely as if they had lived on an island, they seem to have lived and died undisturbed from some great antiquity, if we may judge from the height of the mound, which, as a débris heap, could only have accumulated slowly. Who knows but that here in the Santa Clara Valley is one of the seats where man first invented a stone mill, first loved the glitter and shine of a lovely shell, first raised his eyes and felt that he was different!



NE of the greatest problems which each of the living forms about us has had to solve during the years of its existence on earth is how best to perpetuate its kind during that cold season which once each year, in our temperate zone, is bound to come. Many are the solutions to this problem. Each form of life has, as it were, solved it best to suit its own peculiar case, and to the earnest student of Nature there is nothing more interesting than to pry into these solutions and note how varied, strange, and wonderful they are.

To fully appreciate some of the facts mentioned below it must be borne in mind that there is no such thing as "spontaneous generation" of life. Every cell is the offspring of a pre-existing cell. Nothing but a living thing can produce a living thing. Hence every weed that next season will spring up and provoke the farmer's ire, and every insect which will then make life almost intolerable for man or beast, exists throughout the winter in some form.

If we begin with some of the lowly plants, such as the freshwater algæ, or so-called "frog-spittle" of the ponds, and many of the rusts and fungi which are so injurious to crops, we find that they form in autumn "resting spores." These are very small and globular, one-celled bodies, having a much thicker coat and denser protoplasm or contents than are found in the spores often produced in summer by the same plants, and which are destined for immediate growth. The power of life within these winter resting spores is proof against the severest attacks of frost, and they lie snugly ensconced in the mud at the bottom of pond or stream, or buried beneath the leaves in some sheltered nook, until the south winds of March or April furnish the key to