MAP-CHANGING MEDICINE 



By Willtam Joseph Showalter 



Author of "The Panama Canal," "The Countries oe the Caribbean," "Redeeming the Tropics," "How 



the World Is Fed," "Exploring the Glories oe the Firmament," 



etc., in the National Geographic Magazine 



THREE announcements of almost 

 unprecedented import to mankind 

 are expected to be made at no dis- 

 tant date. 



The first of these, chronologically, at 

 least, will be that yellow fever has at last 

 been banished from the face of the earth, 

 and that the germ which causes it has be- 

 come extinct, along with the dinosaur, the 

 dodo, the great auk, and the passenger 

 pigeon. 



The next in order will probably be that 

 hookworm disease, which has been called 

 "a handmaiden of poverty, an associate 

 of crime and degeneracy, a destroyer of 

 energy and vitality, a menace and an ob- 

 stacle to all that makes for civilization," 

 and which is endemic in a zone that em- 

 braces half of the earth's population, can 

 be driven from any community which has 

 the will to get rid of it. 



Last, but not least in importance, will 

 come the statement that large-scale dem- 

 onstrations have proved that malaria can 

 be eradicated from almost any community 

 that has enough vital force left to push a 

 thorough, though inexpensive, campaign 

 for its extirpation. 



These history-making announcements 

 are safely forecast by an examination of 

 developments in the world-wide warfare 

 on disease being waged by the sanitarians 

 of the world under the leadership of such 

 agencies and institutions as the United 

 States Public Health Service, the health 

 departments of the several States, the 

 British Schools of Tropical Medicine, the 

 India Office, the Dutch Institute for 

 Trjtfpiaal Medicine, and the French Insti- 



Colonial Medicine. 



PREVENTIVE MEDICINE S GREAT VICTORY 



In all the stirring story of man's effort 

 to make himself master of his environ- 

 ment, there is not a more thrilling chapter 

 than that which tells of the bitter battles 

 he has waged for the conquest of con- 

 tagion, and of the ground he has won in 

 his struggle with his relentless and in- 

 numerable, though invisible, foes. 



The World War served to demonstrate 

 that the tyranny of the pathogenic or 

 disease-producing germ can be conquered. 



Straining every nerve for victory, the 

 nations that faced the foe from Bagdad 

 to Bruges had to make sure that epidemic 

 disease should not attack the firing line 

 from the rear. Consequently, half-way 

 and temporizing methods were taboo and 

 preventive medicine had free reign. 



REMARKABLE CONTROL OF EPIDEMICS 

 DURING THE WORLD WAR 



The results were amazing. Although 

 never before in human history was there 

 such an intermingling of peoples, such a 

 crossing and recrossing of seas, such an 

 invitation to contagion to spread to the 

 ends of the earth, only one epidemic suc- 

 ceeded in breaking the barriers erected by 

 the sanitarians. 



And as if to emphasize man's power to 

 master the major contagions, not one of 

 those with which the world's public health 

 officials were familiar escaped from the 

 regions where it was endemic, while in- 

 fluenza, which was a stranger, broke away 

 and swept over the face of the earth. 



India was a hotbed of smallpox. Nine 

 millions of its population were vaccinated, 

 without a single death therefrom, and 

 the disease no longer threatened that 

 land's participation in the war. The 

 Philippines contained enough cases of the 

 same scourge to set the whole world 

 aflame. Millions were vaccinated there, 

 again without the death of a single per- 

 son, and smallpox disappeared. Typhus, 

 likewise, was practically held to lands 

 where it existed before the outbreak of 

 hostilities. 



Conditions in the trenches were such 

 that the battle lines of France might well 

 have become an inferno of infection ; but 

 preventive medicine stepped in and held 

 typhoid fever, malaria, and other commu- 

 nicable diseases in check in a way that 

 was startlingly effective. 



It was natural, therefore, that when 

 peace came again the lessons of preven- 



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