314 FILARl^E AND THEIR ALLIES 



The guinea-worm, though annoying and to one of fine sensi- 

 bilities extremely disgusting, is not in any way dangerous if not 

 interfered with. Should she come to an untimely end, however, 

 or fail to pierce the skin, she may give rise to troublesome ab- 

 scesses, though more often the body becomes calcified and may 

 be felt for years as a hard twisted cord beneath the skin. The 

 crude method of abstraction of the worm which is frequently 

 practiced is the chief source of danger from infection with it. 

 This extraction consists in winding out the extruded part of the 

 worm around a stick, drawing it forth a little further each day. 

 Sometimes this method is successful but frequently it results in 

 the snapping in two of the worm beneath the skin, and the 

 consequent liberation into the tissues of thousands of young 

 worms with the fluid contents of the uterus. This gives rise 

 to inflammation, fever, abscesses and even death from blood- 

 poisoning. 



A much more effective and rational method of treatment is 

 to bathe the part of the body occupied by a mature worm at 

 frequent intervals until she has emptied her uterus, a process 

 which takes two or three weeks. When the birth of embryos 

 ceases, gentle pulling is likely to bring the worm forth, but if 

 not her body is quickly absorbed by the tissues. A more re- 

 cent and quicker method of dealing with a guinea-worm is to 

 inject her body, or the tissue in which she is coiled, with a very 

 weak solution of bichloride of mercury. This kills her and usu- 

 ally makes her extraction easy after a few hours. 



Prevention of guinea-worm infection consists obviously in 

 keeping drinking water clear of Cyclops, or in thoroughly filtering 

 it, or, if these measures are impracticable, in preventing infected 

 persons from bathing in or otherwise contaminating rivers or 

 other bodies of water from which drinking water may be taken. 

 It has been suggested that portable steam generators be used to 

 heat the water in wells, water holes, etc., in which infected 

 Cyclops live, since these crustaceans succumb at a slightly ele- 

 vated temperature. Addition of small quantities of potash to 

 water is also effective in destroying Cyclops. The difficulty 

 connected with an attempt to exterminate Cyclops locally is 

 that the eggs resist desiccation and are blown about freely by 

 the wind, so that a new colony is likely to spring up at any 

 time. 



