THE IMPORTANCE OF PI.ANIS 



in 1938. Tlic difEculty is that most of 

 this annal income is not used. Wocxl, 

 alcoliol produced in fermentation, and 

 plant waste play but a min(jr part in 

 furnishing heat or mechanical energy 

 because of their inconvenience, ex- 

 pense, or lack of adaptability to modern 

 machinery. We depend at present upon 

 coal and petroleum, the world's capital 

 stock of available energ)', to supply the 

 amount required for this mechanical 

 age. 



Berl has reported a method by 

 which motor fuel equal in many re- 

 spects to petroleum can be produced 

 from cellulose, starch, sugar, and other 

 carbohydrates, thus offering the possi- 

 bility of replacing our stock of usable 

 stored energy by utilizing part of the 

 current day-to-day income. Carbohy- 

 drates only can be used by Berl's 

 method; lignin, protein, oils, and fats 

 are unsuitable as crude materials. How- 

 ever, if all the carbohydrates in all the 

 plants were used as Berl suggests, and 

 this is obviously impracticable, we 

 would have but 6 times the present an- 

 nual consumption of petroleum and 

 less than 2 times the equivalent of the 

 annual world consumption of petro- 

 leum and coal. If all the world used coal 

 and petroleum as we did in this coun- 

 try' in 1942, the total energy fixed by 

 plants would be but 25 times that dissi- 

 pated and all the carbohydrates made 

 each year would yield about one-third 

 the amount the world would need. We 

 can only guess what these figures would 

 be if we knew the energy consumption 

 for the war years of 1944 and 1945. 



Two years ago the National Science 

 Fund asked a representative group of 

 outstanding scientists to list the prob- 

 lems with which scientific research 

 should be concerned in the postwar 

 era and on which special emphasis 

 should be placed. Future sources of en- 

 ergy stood third on the list. Its impor- 

 tance was suq^asscd, in the judgment 

 of these men, only by the anahsis and 



study of human behavior and the gen- 

 eral field of medical problems. 



I shall not linger long on the second 

 characteristic of plants so necessary for 

 the existence of other life on this 

 planet; that is, their ability to construct 

 from simple and elementar\' substances 

 t\'pes of chemical compounds essential 

 for animals. Their capacity for making 

 sugar from carbon dioxide and water, 

 constructing amino acids from inor- 

 ganic nitrogen and organic-carbon 

 compounds, and for synthesizing vita- 

 mins enables us to live. Plants are able 

 chemists and there is no substitute for 

 them. 



PLANTS AND RESEARCH IN SCIENCE 



It would seem perhaps appropriate 

 to terminate a discussion of the impor- 

 tance of the plant kingdom after hav- 

 ing pointed out the essential relation 

 of plants to our sources of energy and 

 the dependence of all life on their 

 existence. However, plants do more 

 than fill our stomachs, warm our 

 bodies, and help us to go quickly 

 from here to there. For example, plants 

 are useful for the investigation of 

 problems in science. For this purpose 

 they have certain advantages. They 

 can be grown in large numbers, and we 

 have no compunction in destroying 

 them in quantity if it is desirable for 

 the purposes of the research. Their 

 firm, well-delineated cell walls, gen- 

 eral structure, and methods of repro- 

 duction make them well adapted to 

 the investigation of certain kinds of 

 problems, and their infinite variety in 

 morphology and physiolog)^ offers op- 

 portunity to select an organism best 

 fitted to serve as experimental material 

 for attack on a particular question. 



Tlie study of plants played a major 

 part in the development of our knowl- 

 edge of cells and the formulation of the 

 cell theory. Cells were first described 

 by Robert Ilooke in 1665 from char- 



