ROUNDWORMS 259 



man of twenty may have the size and all the appearances 

 of a child about twelve or fourteen years old. It was long 

 thought that the shiftless and indolent "white trash" of the 

 South were lazy by choice. During the present generation it 

 was shown largely through the important works of Professor 

 C. W. Stiles that they suffered from a disease produced by 

 hookworms. Studies on the life history of the parasite and 

 its methods of getting into the human body were carried on. 

 It was found that only in unsanitary surroundings can the 

 hookworm disease exist, for the young worms get into the 

 soil only when it is polluted by the feces of a hookworm 

 patient. From the polluted soil the young worms come into 

 contact with bare hands and feet and bore their way into 

 the skin. Here they find blood vessels or lymph spaces and 

 are carried by the blood or lymph to the heart. From the 

 heart the larvae are pumped with the blood into the lungs. 

 The minute worms by boring their way through the capil- 

 laries get into the air sacs of the lungs. They then crawl up 

 the air passages into the mouth. The worms reach their 

 final abode in the intestine only after completing this journey 

 through the lungs. After being swallowed they pass in turn 

 from the mouth into the esophagus and thence through the 

 stomach into the intestine. 



It was a triumph of medicine and of zoology when it was 

 discovered that hookworm can be prevented by correcting 

 unsanitary habits and living conditions, and educating the 

 people in proper preventive measures. An equal triumph 

 was the discovery of a simple cure for the disease. With the 

 removal of the worms, the patient not only is saved from 

 the disease but recovers his mental and physical devel- 

 opment as well. The American Hookworm Commission, 

 operating under the generous support of Mr. John D. 

 Rockefeller, has carried on an extensive program of educa- 

 tion in the South. In recent years Dr. M. C. Hall of the 



