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THE NATIONAL GEOGRAPHIC MAGAZINE 



typhoid fever, but got well. Then she 

 returned to her duties as a cook. Six 

 cases of the disease broke out in the 

 family, and she left and was lost sight 

 of for a long time. Although Dr. Soper 

 tried to trace her, it was not until a long 

 time afterward that she was found — 

 this time in service in a family in a small 

 town in New Jersey. Then her history 

 was traced, and it was found that during 

 the time between her two appearances 

 she had cooked in five other homes, and 

 in each and every one she gave the in- 

 mates the disease — 27 cases in all. 



TYPHOID VACCINATION 



But while all sorts of prevention in 

 the line of sanitation help to check the 

 spread of the disease, the final blow was 

 given to it by the discovery of the prin- 

 ciple of inoculation for typhoid. The 

 germs of typhoid are grown in beef 

 broth, and when they number millions 

 for every thimbleful of the broth they 

 are killed by the application of heat. The 

 dead germs are then injected into the 

 blood with a hypordermic syringe, and 

 three doses of these dead germs are 

 nearly always enough to make the body 

 immune from the invasion of live germs ; 

 perhaps because they do not like to dwell 

 amid the sepulchers of their race. 



The success of vaccination for typhoid 

 has been remarkable. In the history of 

 hundreds of thousands of cases only a 

 third as many vaccinated people have 

 contracted the disease as unvaccinated 

 people. Furthermore, the disease termi- 

 nates fatally only a third as many times 

 with vaccinated people as with unvacci- 

 nated ones. In other words, vaccination 

 against typhoid divides the chances of 

 dying from the disease by twelve. 



Typhoid fever, however, is not so much 

 of a tropical scourge. It does flourish in 

 semi-tropical countries and among white 

 people who go to the tropics. The na- 

 tives seem to be rather immune from it, 

 mayhap because the typhoid germ re- 

 fuses to dwell in the same body with 

 nmrcbic dysentery germs, with which so 

 many tropical people are afflicted. But 

 the lessons which our studies of the prin- 

 ciples of the spread of typhoid fever have 

 taught us fit in so beautifully in tropical 



campaigns to master dysentery and chol- 

 era that they are almost as serviceable in 

 the tropics as they are in the temperate 

 zones. The fly carries the germ of chol- 

 era and of dysentery just as it carries the 

 germ of typhoid. These germs use the 

 same vehicles and travel in the same gen- 

 eral way from the intestines of one per- 

 son to the mouth of another. 



The sum of all of these discoveries is 

 that they place in the hands of mankind 

 the power to overcome the most terrible 

 diseases with which the tropical world 

 has been afflicted. 



CAPITALIZING THE DISCOVERIES 



And now, having looked far into the 

 past to see the vast need there has been 

 for such discoveries, and into recent his- 

 tory to learn something of how they were 

 made, let us journey around the tropical 

 world today and see how they are being 

 applied. 



Of course, we go first to Panama, for 

 there they are being applied on a scale 

 that is extensive and with a thorough- 

 ness that shows the possibilities of such 

 application. Indeed, no factor for putting 

 the new science of tropical medicine to 

 the most rigid test is wanting there. 



Before the United States took control 

 and Colonel Gorgas began to apply the 

 lessons that had been learned in Cuba, 

 yellow fever was endemic, malaria al- 

 most universal, bubonic plague not ex- 

 ceptional, and smallpox not infrequent 

 in its occurrence. Things had been so 

 bad that they defeated the French in 

 their efforts to dig the Panama Canal, 

 and when the despair of the bubble-burst 

 boom days settled like a night over the 

 wrecked hopes of the French failure, 

 conditions grew even worse. 



Colon was a swampy mire of filth 

 which bade warm welcome to every germ 

 that came along, and extended hearty 

 hospitality to every mosquito and flea 

 that traveled that way, bidding them all 

 to "be fruitful and multiply" — an invita- 

 tion as heartily and as appreciatively ac- 

 cepted as it was extended. 



Panama offered a haven to every dis- 

 ease borne upon the wings of commerce. 

 The water-carriers who peddled water 

 from contaminated springs became the 



