344 



THE NATIONAL GEOGRAPHIC MAGAZINE 



stroys, but individual screech-owls are 

 often destructive to bird life. 



Crows and jays will bear watching. 

 There seem to be good crows and jays, 

 and then again individuals among them 

 of exceeding bad habits, as many a long- 

 suffering bird family knows to its sorrow. 



In many places the English sparrows 

 are pests and should be shot and trapped 

 relentlessly. They are pretty canny 

 birds, and if once they learn you are af- 

 ter them with a gun they quickly desert 



the premises. If owing to surrounding 

 conditions gunning for them seems un- 

 desirable, traps may be used with telling 

 effect. There are several kinds in use in 

 this country. 



Last, but not least, the black snake 

 should be killed whenever found; its 

 large size, great activity, tree-climbing 

 propensities, and taste for eggs and small 

 birds have fairly won for it the reputa- 

 tion of being one of the birds' deadliest 

 enemies. 



REDEEMING THE TROPICS 



By William Joseph Showalter 



Author of "Battling with the Panama Slides/' "The Countries of the Caribbean;' 

 '"The Panama Canal," in the National Geographic Magazine 



IN THESE days when medical science 

 has been recording one triumph after 

 another over germ-produced diseases, 

 when the ge.i;m-hunter in his laboratory 

 has been ascertaining the causes of so 

 many mysterions afflictions and laying the 

 foundations for one preventive measure 

 after another, people all but lose sight of 

 the tremendous debt humanity owes to 

 the expert in experimental medicine and 

 the sanitarian. Indeed, he would be a 

 prescient mathematician who could calcu- 

 late what the vast amount of this debt is. 



It is only when we look back over the 

 records of the past, when civilization was 

 young and humanity without knowledge 

 of the causes of the great epidemic dis- 

 eases, that we can have a faint appreci- 

 ation of what the patient man of the 

 microscope has wrought in humanity's 

 behalf. 



When we see Naples, in the seven- 

 teenth century, as helpless as a new-born 

 babe in the grip of a plague during which 

 380,000 souls perished in six months ; 

 when we see Constantinople, in 18 12, with 

 144,000 deaths; when we see London, in 

 the days of the great plague, with 70,000 

 of its population carried off ; when we go 

 back to China and behold a few short 

 years in the fourteenth century with a 

 "black death" mortality record of 13 mil- 

 lion souls, and to Europe, in the great 



scourge of 1347- 13 50, and see 25 million 

 people dying; when we come on down 

 the years and see the untold millions who 

 have died from the numerous pestilences 

 which have inflicted death upon mankind ; 

 then, and not till then, can we begin to 

 appreciate what it all means. 



Even then our appraisal will fall far 

 short of the truth, for in those times the 

 world was, in a sense, larger, the seas 

 were broader, and the distances on land 

 much greater than in these days of highly 

 developed transportation and commerce. 

 How can the mind conceive of the terri- 

 ble toll epidemic diseases would take to- 

 day, with our world-wide commerce, 

 with our metropolitan and cosmopolitan 

 cities, and with the constant commingling 

 of the peoples of all lands, were it not 

 for preventive measures ? 



MAP-CHANGING MEDICINE} 



Throughout the history of the ages one 

 may read of great changes in the maps 

 of the earth that have resulted on the one 

 hand from the ravages of disease and 

 on the other from the discovery of meth- 

 ods of combatting it. 



We see the "glory that was Greece" 

 depart because of the terrible toll exacted 

 by malaria ; we see a Panama Canal made 

 possible because of the knowledge of the 

 causation of yellow fever that came to 



