The more we study the distribution of organized life on the globe, the more we tend to abandon the hypothesis of migration. The Andes chain divides the whole of South America into two unequal longitudinal parts. At the foot of this chain, on both east and west, we found many plants that were specifically identical. The various passes on the Andes would not let any vegetation from warm regions cross from the Pacific coast to the Amazon banks. When a peak reaches a great height, whether in the middle of low mountains and plains, or in the center of an archipelago raised by volcanic fires, its summit is covered with alpine plants, many of which are also found at immense distances on other mountains under similar climates. Such are the general phenomena of plant distribution.