Biology and Medicine 465 



footed were anemic, run down and unable to do good work, 

 and the Italian Perroncito at that time traced the disease to 

 the hookworm Ankylostomum duodenale. Some years later 

 the German Looss, traced the course of the worm from the 

 infected soil to the intestine of its victim by a very clever bit 

 of biological detective work. There had been known for many 

 years an irritation of the skin of the feet under the names 

 of "ground itch," "foot itch," "dew itch," etc. 



(a) FEMALE, (b) MALE, AND (c) MOUTH OF THE HOOKWORM 

 An animal which is mainly responsible for the condition of the ''poor 

 whites ' ' in the South, and which causes an economic loss of perhaps 

 $500,000,000 annually. The disease can be effectively and easily cured, 

 while its prevention is merely a matter of a few simple sanitary pre- 

 cautions. (After Stiles.) 



"While experimenting with hookworm larvae he spilled 

 some of them on his hand; he noticed a burning sensation 

 and in a few minutes the larvae had disappeared. After the 

 proper interval, about two months, he found himself suffer- 

 ing with the hookworm disease. To determine what had be- 

 come of the larvae that were spilled on his hand he poured 

 some larvae on the leg that was about to be amputated from 

 a boy; on sectioning the skin of this leg, after amputation, 

 he found the larvae had worked their way through the skin 



