278 PUBLIC PARKS OF IOWA 



about, and the waters are soon befpuled. The vegetation does not make 

 such places foul. Where green plants grow freely in water there the 

 water is pure, for the green plants themselves purify it not only by ab- 

 sorbing materials which would pollute the water, but by setting free 

 oxygen which also disposes of undesirable materials. When finally late 

 in the season they die and are left stranded by the falling of the water 

 surface, they decay so quickly that no evil results follow, there being 

 only a little fertile material left for the next crop of plants. The foulest 

 bodies of water are those to which stock has free access, and in which 

 the green vegetation is soon destroyed. Yet we permit stock to enter 

 freely such bodies of water as Spirit lake, the Okoboji lake, Storm lake, 

 Clear lake and others, notwithstanding the fact that the water ot the 

 lakes is often used for domestic purposes, as is the case in Milford for 

 example, and the further fact that thousands of people bathe in these 

 waters during each summer season when the danger is greatest! Surely 

 those who are responsible for this should not be permitted to use the 

 resulting condition as a pretext or excuse for draining the impure lakes, 

 which result from this practice. The lakes may easily be kept pure, and 

 this chiefly by keeping out stock. 



There is still another reason for conserving portions of our state. 

 This may not appeal to a large number of people, but it is important never- 

 theless. There is need of saving a part of our native vegetation under 

 original conditions for scientific purposes and studies, not merely that 

 the student may find plants for study, but that investigations of our 

 native flora may be continued with a view of determining the influence 

 of various conditions upon plant life. The native flora presents many 

 advantages for this purpose, for it represents the final outcome of all 

 the influences which have acted upon plants in time past; and it offers 

 a much better measure of the value of these influences than could any 

 artificially introduced and cultivated plant. The results so obtained 

 are of value in their application to the control of cultivated plants, but 

 the results themselves can be more readily and satisfactorily obtained 

 by the study of native plants. For these purposes and for the benefit 

 of the students yet to come the tracts conserved for the other purposes 

 mentioned would serve very well and their desirability simply adds another 

 argument to those which may be offered in favor of the establishment 

 of such reservations. Our children should have an opportunity to see 

 at least suggestions of what the state once was. 



In the line of positive suggestions towards the carrying out of a plan 

 for the conservation of natural tracts and conditions the following 

 possibilities are presented: 



1. So far as possible preserve the tracts (especially where forested) 

 which border streams and lakes and use them also as game preserves. They 

 may likewise serve locally as parks and local support could probably be 

 secured if they were so used. 



2. On the hills bordering the Missouri valley there are still tracts 

 of almost undisturbed prairie. Much of that land is not of great agri- 

 cultural value. Some of these tracts should be preserved that future 

 generations might have an opportunity to study and enjoy the original 

 prairie. 



