ZOOLOGY AND HUMAN WELFARE 



some remarkable discoveries have been made, such, for 

 instance, as the relation between shoes and shiftlessness. 

 We commonly assume that shiftlessness leads to going 

 barefoot; but in hookw^orm regions the opposite is more 

 likely to be the case. 



The victim of a hookworm infection becomes weak and 

 pale; growth and development are retarded, so that a 

 person of twenty may appear to be twelve; in girls the 

 breasts fail to grow; the face is bloated, the eyes staring; 

 a craving to eat dirt becomes strong; dizziness, headache, 

 profound stupidity, illiteracy, and weak resistance to other 

 diseases appear as common symptoms; and of course 

 industrial ability and efficiency are low, and a retarded 

 civilization marks the place where from 30 to 100 per cent 

 of the people harbor the parasites. The worms are about 

 one-half inch in length, and thousands of them may live in 

 the intestine of a single patient. There they cause unhealing 

 sores from which blood is constantly lost; and they give off 

 poisonous secretions which seem to cause most of these 

 distressing symptoms. The eggs of the worms are dropped 

 on the ground in the faeces of the host, where the young 

 worms develop and live in the surface soil for six or eight 

 weeks. Then they die . . . unless a barefoot boy happens 

 along. If he steps on a young worm, it bores immediately 

 into the skin of the foot, travels through the blood vessels, 

 heart, lungs, esophagus, and stomach, and finally reaches 

 the intestine, where growth is completed and reproduc- 

 tion occurs. Before long, the boy loses his tan and other 

 attributes of vitality, becomes shiftless, and, when his turn 

 comes, fails to provide his children with shoes, the greatest 

 blessing that could have been given him when young. 

 Thus it is that the lack of footwear makes shiftless people. 

 All of this was quite unavoidable until the zoology of the 

 hookworm was known, whereupon methods of control 

 were clearly seen. First, prevent infection of the soil by 



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