With every mile that one advances into the more rainy interior, the jungle becomes greener and fresher, the density of the lower growths increases, and the proportion of large trees becomes greater until finally jungle gives place to genuine forest. There many of the trees remain green throughout the year. They rise to heights of fifty or sixty feet even on the borders of their province, and at the top form a canopy so thick that the ground is shady most of the time. Even in the drier part of the year when some of the leaves have fallen, the rays of the sun scarcely reach the ground until nine or ten o'clock in the morning. Even at high noon the sunlight straggles through only in small patches. Long, sinuous lianas, often queerly braided, hang down from the trees; epiphytes and various parasitic growths add their strange green and red to the complex variety of vegetation. Young palms grow up almost in a day and block a trail which was hewn out with much labor only a few months before. Wherever the death of old trees forms an opening, a thousand seedlings begin a fierce race to reach the light. Everywhere the dominant note is intensely vigorous life, rapid growth, and quick decay. In their effect on man, the three forms of tropical forest are very different. In the genuine rain forest agriculture is almost impossible. Not only does the poor native find himself baffled in the face of Nature, but the white man is equally at a loss. Many things combine to produce this result. Chief among them are malaria and other tropical diseases. When a few miles of railroad were being built through a strip of tropical forest along the coast of eastern Guatemala, it was impossible to keep the laborers more than twenty days at a time; indeed, unless they were sent away at the end of three weeks, they were almost sure to be stricken with virulent malarial fevers from which many died. An equally potent enemy of agriculture is the vegetation itself. Imagine the difficulty of cultivating a garden in a place where the weeds grow all the time and where many of them reach a height of ten or twenty feet in a single year. Perhaps there are people in the world who might cultivate such a region and raise marvelous crops, but they are not the indolent people of tropical America; and it is in fact doubtful whether any kind of people could live permanently in the tropical forest and retain energy enough to carry on cultivation. Nowhere in the world is there such steady, damp heat as in these shadowy, windless depths far below the lofty tops of the rain forest. Nowhere is there greater disinclination to work than among the people who dwell in this region. Consequently in the vast rain forests of the Amazon basin and in similar small forests as far north as Central America, there are today practically no inhabitants except a mere handful of the poorest and most degraded people in the world. Yet in ancient times the northern border