PREFACE 



Discovery is pushing forward in every direction as never 

 before in the history of the world, and still it would seem 

 that enough is already known to make living well-nigh ideal 

 and the world almost a paradise, if only enough people knew. 

 In how many of our civic units does every citizen know 

 enough to conserve effectively the valuable bird life, the trees, 

 the soil, and water on his own premises, to exterminate the 

 rats and English sparrows, the flies, mosquitoes, and San Jose 

 scale, the hookworms, diphtheria, and tuberculosis germs ? If 

 every individual citizen knows enough to do these things, 

 in how many communities do all the people know enough 

 to cooperate, to work together with efforts so timed and 

 planned that the good work of one, or of all but one, shall 

 not be rendered vain by the failure of someone else to do 

 his part? 



The tides and currents, storms and floods, of living nature 

 are too vast and powerful to be held within any dikes less se- 

 cure than those built by the common, united effort of the whole 

 community. The measure of our present need is seen in the 

 wastage and loss that is streaming through our ineffectual 

 defenses, the probably not less than five hundred thousand 

 valuable lives sacrificed annually to the currents of prevent- 

 able disease, along with the several billions of dollars' worth 

 of foods and other property swept away by rats, insects, 

 weeds, and fungi. How much higher must the cost of living 

 soar before we begin to awake from the dream that we are 

 a scientific and efficient people ? As we are now organized 



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