Part 200. Plants in general. The foregoing reflections upon the way natural objects are related to one another are intended especially to emphasize the pivotal place which plants hold in the economy of nature. It is now believed that the wide and rich possibilities of earthly life could not have been gained or maintained without plants. Plants were presumably the first things to manifest individualized powers of choice upon our planet; and plants have so chosen that animals have been born and enabled to realize the highest opportunities of life. Hence, because some plants have chosen as they did, we are now able to choose as we do.

One of the earliest results of plant choice was doubtless the fixed mode of life; and with this we may connect the building of a protective cellulose covering and framework readily permeable by fluid raw-food materials. The firmness of this framework, combined with its power of conducting fluids, permitted eventually the building, even upon land, of enormous structures hundreds of feet in height. Fixity, together with their powers of absorption, have thus enabled plants to attain in some cases the longest life and the greatest size of any organisms. Preferring to be home-keepers rather than hunters their more tranquil lives have given neither opportunity nor occasion for such specializations of sensitiveness as are involved in the rapid and highly complex responses of animals. Hence it is that their modes of life appear so different from ours although but modified manifestations of the same fundamental, vital power.

It is just because of the contrasts between vegetable and human life that plants are able to serve our needs in so many ways. They feed us because they have retained the power of food-making which our line of life has lost. They shelter us because they have learned how to form in wood a constructive material better than any we or our ancestors could ever make. They clothe us because the cellulose fibers of their bodies make a better covering than the hairs our bodies have retained. They warm us and work for us because they can store up sunshine, as we cannot. They help to make us well partly because their waste-products are so different from ours. They excite our admiration by doing to perfection so many things we cannot do at all. They harm us only when we have not learned to know them and to behave toward them as we should. There are thus abundant reasons why mankind should study the economic properties of plants as fully as possible. We may be sure there will always be much to learn regarding the relations of plants to human welfare, and that all we shall learn about this or any other aspect of their lives may serve to enrich our own. Thus, an inexhaustible interest as well as an increasing command over the resources of our world is the reward of our endeavor.

An even deeper interest than belongs to any idea of use or harm is also sure to be aroused by watching the behavior of these our fellow-creatures that are so different from us in almost every way. For, again, these very differences give them an endless fascination as objects of study; and, finally, it is just these differences which enable us to distinguish the incidental from the essential powers of life. In these organisms we see individualized wills expressed under conditions as different as possible from those which permit the action of our own power of choice. We cannot hope to fathom the mysteries to which the humblest plant may lead us; we can only say with the poet Tennyson-

"Flower in the crannied wall. I pluck you out of the crannies, Hold you here, root and all, in my hand, Little flower-but if I could understand What you are, root and all, and all in all, I should know what God and man is."