ROUNDWORMS— THE NEMATHELMINTHES 



159 



There are a number of drugs which seem very effective against them such 

 as oil of chenopodium and hexylresorcinol, so there is no excuse for a 

 person tolerating the infection when the worms can be rather easily 

 expelled. 



The Hookworm 



There is a much smaller roundworm which causes body symptoms 

 that are much more serious than those caused by ascaris. This is the 

 hookworm which gets its name from the hooked body of the male. The 

 scientific name, Necator am eric ami s , literally means American killer and a 



Courtesy Army Inst, of Pathology 



Fig. 11.4. Photomicrograph of the anterior part of a hookworm attached to the in- 

 testine. Note the part of the intestine extending down into the hookworm's mouth. 



study of its depredations will justify the name. It lives in the small in- 

 testine, but does not absorb the digesting food like ascaris ; instead it bites 

 the intestinal wall and sucks blood and, since it moves around quite a bit, 

 it does extensive damage to the intestine and there is quite a bit of bleed- 

 ing at a spot after the worm has moved to another place. The excretory 

 wastes of a number of these worms cause a general physical and mental 

 retardation and a typical "shiftlessness" that, for many years, was char- 

 acteristic of a great proportion of the population in many of our southern 



