The struggle for existence among the plants and trees is keen beyond imagination. And the struggle among the insects, birds and beasts, and man for the plants and products of the trees is no less severe. So now our impression is that of an abundant, varied and intense life in which the individuals are perpetually struggling with one another for bare existence. * * * Under these stringent and stressful conditions does each living being come into the world. He has to battle his way through--or succumb. Plants as well as men, and men as well as plants. So, as we look into the structure of animals and plants, we are not surprised to find that in order to cope with their surroundings they have developed organs which are specially adapted to enable them to secure the needful food, to hold their own against the competition of their neighbours, to meet the exigencies of their surroundings, and to pursue their own life to the full extent of its possibilities. Even plants are like sentient beings in this respect. The sensitive tips of their roots are organs admirably adapted for feeling their way through the soil and selecting from its constituents what will best nourish the plant. The leaves opening out to the air and sunshine are other organs adapted for gathering in nourishment. And thorns and poisonous juices are means adapted to fend off destructive neighbours. The eyes and ears in animals are other instances of organs which enable them to see what will serve them as food, or to hear what may be possible enemies, and to make use of what will help them to the proper fulfilment of their life. We see each individual plant and animal striving to the best of his ability to adjust himself to the conditions in which he finds himself, trying to adapt himself to his surroundings--to his physical surroundings, such as the climate and soil, and to his social surroundings, consisting of his plant and animal neighbours and rivals. We shall probably notice, too, that he seems to be driven by some inner impulse (which in its turn is a responding to the impress of the totality of the individual's surroundings) to strive to do something more than merely adapt himself to his surroundings. He is urged on to rise superior to them.