learn to distinguish the useful plants among those which were not useful. It is not an easy task to pick out, in the three or four hundred thousand species of which the existing flora is composed, those most suitable for satisfying various wants—especially when we recollect that most of the uses we make of them, instead of being naturally indicated, are suggested by previous discoveries, and that there is no motive to impel one to seek in things a utility which is not suspected.
Primitive man was doubtless put in the way of making such discoveries by pressing necessities and the suggestion of chance. The terrible famines to which savages are exposed, which force them to eat the most insignificant berries, grasses, roots, and even the leaves of trees, caused them to learn by repeated trials the productions which could best afford them nourishment. Attention was fixed upon the most advantageous and least repulsive of them. Such experimentation, marked by disgusting and perilous features—for many poisonous plants proffer baits to greedy appetites by which they are sometimes caught—was accomplished at the instigation of hunger, with the assistance of instincts then more formal or better minded than now, comparable to those which guide animals so surely in the choice of their food. At a later date, nascent reason discovered various useful qualities in plants. Fortunate observations and trials followed by success showed what profit could be derived from products long neglected. The uses of wood assigned an increasing importance to it, first as a combustible, beginning with the discovery of fire, then as a substance that could be made serviceable in infinite ways. In time, men learned to separate, twist, spin, and weave bark and fibers, to color them in various shades, and to extract oil, wine, and sugar. Casual cures revealed the medicinal properties of simples. Every age saw an increase in the number of useful products which one could draw from plants. Even now, after the many investigations that have been pursued through thousands of ages, we are far from having made available all the resources which the vegetable world might furnish us; and its fertility holds in reserve for us many treasures of which we are still ignorant.
All the plants that have come into cultivation among us were first used wild, for their value had to be recognized before the thought of multiplying them could take shape. As long as they were naturally abundant enough to suffice for the necessities of sparse populations, no pains would be taken to propagate them. This phase of absolute uncultivation, the longest that the human species has traversed, appears to have continued from the origin of the race to the present geological period. Nothing, in fact, in the vestiges that have come down to us of that age reveals any signs of cultivated plants or of modes of cultivation; and such are
