396 



SCIENCE 



[N. S. Vol. LII. No. 1348 



population of tlie eartli increases. There will 

 be of course temporary local short-time food 

 shortages due to unfavorable seasons, wars, or 

 other vmusual conditions. These situations 

 will have to be met as best they can at the 

 time. The thing to which I should like to 

 direct attention at present is not this tem- 

 porary condition of famine but rather the 

 means by which people may be fed when the 

 world becomes much more populous than it 

 now is. Having an earth, the best land of 

 which is already producing crops without any 

 great surplus, how is it going to be possible 

 for nations to grow, cities to be built, and 

 civilization to advance? Is there a limit to 

 the number of people for whom the earth can 

 supply food, or can the increase go on 

 indefinitely? 



As a small boy I remember going through 

 what seemed to me to be an immense forest 

 with a man who said it contained enough 

 timber to last the whole United States for a 

 thousand years. In later years when I be- 

 came old enough to make the calculation, I 

 found that this particular body of timber 

 would not furnish America's needs for a 

 single year. 



In the early days of the settlement of the 

 west many who saw the large rivers made the 

 statement that the water of these rivers could 

 never be exhausted by imgation. The supply 

 was said to be limitless. Experience has 

 shown that the water of many of these 

 streams was exhausted before more than a 

 fraction of the adjacent land could be served. 

 Thus, all things have their limits. There is 

 a limit to the number of people a given area 

 of land can sustain, and since the area of land 

 is practically constant there must be a limit 

 to the number of people that can be fed. The 

 number of course depends entirely on how 

 fully the resources of the earth are utilized. 

 It is possible greatly to increase production. 

 I wish particularly to call attention to the 

 methods by which the agronomist may assist 

 in accomplishing this end. 



I am not an alarmist. I do not wish to ap- 

 pear as one who is trying to stir people up 



unnecessarily. I should not even like to take 

 the responsibility assmmed by Sir William 

 Crookes, who, in his presidential address be- 

 fore the British Association for the Advance- 

 ment of Science in 1898, set a date when the 

 shortage of food would begin to be felt. I 

 do not believe that there is sufficient data 

 available for any one to be so definite. A few 

 facts, however, may be used to help in clarify- 

 ing our minds on the subject. 



It is well known that the population of all 

 important countries of the world is gradually 

 increasing. During the 110 years from 1800 

 to 1910 the population of the world increased 

 from 640,000,000 to 1,600,000,000, or an in- 

 crease of 152 per cent. Only a few genera- 

 tions ago there were vast continents of un- 

 settled fertile land waiting to absorb the over- 

 flow from the populous parts of the world. 

 There are still many large tracts of land that 

 are not settled, but it is obvious to all who 

 have made a study of the subject that the 

 better lands are rapidly being put under culti- 

 vation, and only the more remote and more 

 imfavorable areas remain. This does not say 

 that there is not still available much excellent 

 land, but let us consider the United States 

 as an example. 



In 1790 the population of the entire coun- 

 try was 3,929,214; by 1840 it had reached 

 17,059,453; while the 1920 census shows it to 

 be more than 105,000,000. A century ago 

 only the east coast was settled; the great heart 

 of the agricultural land had not been touched. 

 The rapidity of settlement of the middle 

 northwest is indicated by the fact that be- 

 tween 1800 and 1820 the population of Ohio, 

 Indiana, Illinois, Michigan, Wisconsin and 

 Iowa was increased from 50,240 to 792,719, 

 and by 1840 it had reached 2,967,840. To- 

 day the entire country has been thoroughly 

 explored and the better land has been pro- 

 ducing for nearly a generation. 



In order to see just how our production and 

 consumption have balanced during the last 

 three score and ten years — the allotted time 

 of man — let us examine the figures for wheat, 

 probably our best index crop. 



