PLANTS IN GENERAL 575 



presumably the first things to manifest individuahzed powers 

 of choice upon our planet; and plants have so chosen that 

 animals have been l)orn 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 \vt 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 sensitive- 

 ness as are involved in the rapid and highly complex re- 

 sponses of animals. Hence it is that their modes of life 

 appear so different from ours although but modified mani- 

 festations 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 con- 

 structive 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 perfec- 

 tion 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 



