PREFACE 



Discovery is pusliiug forward in every direction as never 

 before in the liistory 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 kne\A-. 

 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 Hies, mosquitoes, and San Jose 

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

 every individual citizen knows enouo^h to do these thinos, 

 in how many communities do all the people know enough 

 to cooperate, — to work together Avith efforts so timed and 

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

 not be rendered vain bv 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 wliolc 

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

 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 Avith the several billions of dollars' \\orth 

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

 weeds, and funoi. Mow nuich hicfher nuist the cost of livincj 

 soar before we beo'in to awake from the dream that we are 

 a scientific and elhcient people? As we are now organized 



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