BIOLOGY AND HUMAN WELFARE 417 



probably contribute at least as greatly to this indispensable work. 

 Ground burrowing insects are still more widely distributed than 

 Earthworms and in most regions they are more numerous and more 

 active. Moreover, not only do they carry decaying leaves beneath 

 the soil, but also rich nitrogenous plant food such as manure and 

 the dead bodies of animals. (Fig. 266.) 



Finally, it is not an exaggeration to wonder how land plants 

 could have arisen without the direct or indirect services of insects. 

 Indeed geological history indicates that land plants did not flour- 

 ish and Seed Plants did not exist before insects became a well- 

 established part of the Earth's fauna. 



Enough, perhaps, has been said to indicate the struggle for 

 knowledge which Man must maintain in order to cope with the 

 biological forces that would rob him, are robbing him, of what he 

 considers his heritage. But it is only fair to add that biologists 

 who have given the most thought to the problem are by no means 

 certain that the struggle will eventually be successfully terminated; 

 it is possible that insects and allied enemies will gain the upper 

 hand in the warfare for food when the human population has in- 

 creased beyond a certain limit. This seems incredible, though 

 it is a conservative statement by men who are specialists and not 

 pessimists. In any event, it is clear that the most urgent need to- 

 day is more knowledge of the life habits of insects and other de- 

 structive organisms. Generous Federal and State appropriations 

 must be made so that through research effective methods of con- 

 trol may be developed. Experience has shown that the research 

 dollar is not only invested in a gilt-edge security, but one at the 

 same time producing a national dividend almost beyond com- 

 putation. (Figs. 270, 271.) 



C. Conservation of Natural Resources 



We are slowly awakening to the fact that we have been very 

 shortsighted. Conservation of natural resources has, until re- 

 cently, given very little concern, although it is one of the greatest 

 problems which biologists of the present generation face, and it 

 must be solved now or it will be too late. What happened in 

 America is being repeated in many other parts of the world. Our 

 forefathers came to a land of fertile soil covered with primeval 

 forests, abounding with large and small Birds and Mammals, and 



