Such unfortunate occurrences are sure to become more and more infrequent as plant emigration and immigration finds itself under increasingly drastic governmental regulation. The Foreign Seed and Plant Introduction Service of the United States Department of Agriculture makes a scientific examination of all plants brought into the United States for propagation purposes. It rids them of objectionable Bacteria and insect pests and refuses them admittance entirely if its experts decide that the newcomers will be harmful or injurious in any way. The agents of the Service are constantly scouring the far corners of the earth for new and rare plants. In the twenty-four years of its existence it has introduced from abroad some fifty thousand specimens of seeds and plant cuttings. Some of the successful immigrants have been Feterita (from Egypt), Sudan Grass, Bamboo and Alfalfa. New Zealand has yielded new types of Potatoes. Dwarf Almonds and strange Cherries and Apricots have come from Turkestan. All these have proven of commercial importance, as has Durum Russian Wheat, credited with opening up new areas in the Northwest, and the Navel Orange from Brazil which has created for itself a California industry covering thirty thousand acres and valued at fifteen million dollars per annum. Painstaking and scientific methods are best when man attempts to aid Nature in her evolutionary processes, especially when they are in connection with the migration and distribution of plants. CHAPTER IV COMRADES OF THE PLANT WORLD “... _which links by a fraternal tie The meanest of His creatures with the high._” --_Lamartine_ The first and greatest problem for every terrestrial creature is to live. The chief means of doing so is to eat. Therefore, the relation of being to being and species to species is dominated by the necessity for food. Among man this fact is somewhat masked and obscured, but in the rest of the world it is entirely plain and obvious. Again and again on every hand, we see that plant, animal, and man all maintain their life impulses by consuming the tissue of their fellows. In view of this fundamental fact, we can afford to look with some degree of charity upon that class of plants which are termed parasites. These interesting creatures are merely carrying out in a very direct and apparent way a principle which permeates all domains of life. A Tiger kills its prey; an Ox devours unoffending Grass; the parasitic Dodder robs some healthy neighbour of part of its juices.