THE AUSTRALIAN MUSEUM MAGAZINE. 



147 



The Story of the Hookworm. 



By Dr. Wilbur A. Sawyer, 



Senior State Director International Health Board of the Rockefeller 

 Foundation, and Director of the Australian Hookworm Campaign. 



[Abstj-act of a lecture delivered at the Australian Museum, April 13, 1922.] 



The hookworm is one of the nematodes, 

 which on account of their shape are com- 

 monly called thread worms or round 

 worms. Their early ancestors doubtless 

 lived in earth or water as the more primi- 

 tive nematodes do to-day, but, with the 

 lapse of time, this class of worms became 

 diversified and adapted to various en- 

 vironments. Some made their home in 

 decaying vegetation, others learned to 

 penetrate living plants, and still others 



comprising a number of genera and spe- 

 cies. Each species is parasitic in a spe- 

 cial host; the dog, the cat, the sheep, the 

 cow, the seal, the elephant, man, and 

 doubtless many other animals, each have 

 their particular species of hookworm 

 parasite. Two species are parasitic in 

 man, Necator amerioanus, the common 

 hookworm of the tropical belt, the South- 

 ern Hemisphere, and North America, and 

 Ancylostoma duodenale, which predomin- 



Hookworm demonstration at a country public school. Fart of the campaign is an effort to 



interest the children, who in turn become missionaries in the cause, and thus carry the pro 



paganda from home to home. Much good work has been done in this direction. 



acquired the power to live on the highly ates in northern Africa, northern India, 



nutritious tissues of living animals, or on 

 the partly digested contents of their in- 

 testines. 



Among the nematodes which are thus 

 parasitic on animals are the hookworms. 



China, and Europe. In Australia, Neca- 

 tor americanus is the commoner form, but 

 there is a small admixture of the other, 

 probably introduced from Europe, and 

 both varieties mav be found in the same 



