326 



THE NATIONAL GEOGRAPHIC MAGAZINE 



Photograph by Charles Martin 



A MOTHER WITH A SICK BABY CONSULTING A "MEDICINE MAN" I PHILIPPINE ISLANDS 



"There are many people on the earth who still believe that the snake is the only potent 

 healer ; more who still believe in the 'evil eye' ; those who try to get rid of tuberculosis by 

 swallowing" a live frog; those who eat fox lungs to improve their 'wind " (see text, page 330). 



its extinction is thought about ready to 

 strike, and, like the dinosaur, it will die 

 out chiefly because it is a victim of over- 

 specialization. 



It is believed once to have been an in- 

 habitant of the blood of various rodents ; 

 then some mosquito carried it from ro- 

 dent to man, and it found its new en- 

 vironment so much to its taste that it 

 refused to thrive in its old habitations 

 any longer. It came to be wholly depend- 

 ent on man for its habitat and on the 

 mosquito for its transportation. Elimi- 

 nation of its vehicle of transportation 

 means inevitably its extinction. 



In the course of their work for the 

 eradication of yellow fever, the sanita- 

 rians find that the employment of surface- 

 swimming minnows is a better way of 

 combatting the mosquito than the use of 

 an oil film on the surface of the water, 

 because less expensive and more constant. 



Hardy, multiplying rapidly, and always 

 seemingly as hungry as wolves, these 

 minnows are able to control the mosquito 

 situation in 85 per cent of the waters in 

 which they are introduced. 



In 19 1 9 a big epidemic of yellow fever, 

 with more than 3,000 cases, broke out in 

 northern Peru. The lessons learned at 

 Guayaquil were applied to check it. The 

 little top-minnow was put to work and 

 proved an amazingly valuable ally in ban- 

 ishing the disease from the region. 



WHEN-THE-BCZZARDS-EXTERED-THE- 

 IIOUSE DISEASE 



It has been advanced as a theory by 

 students of Central American archeology 

 that yellow fever was responsible for 

 the fall of the highly developed Maya 

 civilization, and that the majestic ruins 

 at Mitla, Palenque, Chichen Itza, Peten, 

 Quirigua, and elsewhere, from Yucatan 

 to Honduras, are eloquent testimonials of 



