TREATMENT AND PREVENTION 237 



or liver, but may attack other parts of the body such as the 

 muscles, eye and even the brain. They do injury both by me- 

 chanical interference with the organs and tissues, and by the 

 accumulation of poisonous waste products which may be ac- 

 cidentally liberated. Only by surgery can such bladder worms 

 be removed, and surgery is often impossible on account of the 

 numbers and positions of the bladders. 



Treatment.. — Preparatory to treatment for adult tapeworm in- 

 fections the patient is put on a Kght diet and his bowels cleared out 

 so that the parasite may meet with no obstruction in its passage 

 through the intestine. The drugs which have been found most 

 useful in expelling tapeworms are male fern, pelletririne and 

 thymol7 These drugs are dangerous if not taken properly, and 

 none should be taken without the supervision of a physician. 

 Thymol, for instance, while ordinarily quite harmless since it is 

 not absorbed by the intestine, is soluble in alcohol and certain other 

 substances and may cause death if taken along with these things. 

 Oil of chenopodium, which has recently come into great favor 

 for expelling hookworms and is even more efficient for certain 

 other nematodes, has been found valuable for expelling dwarf 

 tapeworms, Hytnenolepis nana, and would probably be equally 

 effective for other species. 



After the drug is administered a purgative is given which tends 

 to drive the parasite out. The latter should be passed into a 

 vessel of warm water, since sudden contact with cold stimulates 

 the nervous system of the worm and causes it to contract sud- 

 denly, thus often breaking it before it has been completely ex- 

 pelled. A careful search for the head should be made, and if 

 not found the treatment should be repeated in the course of a 

 week or ten days. 



Prevention. — Prevention varies, of course, with the species of 

 tapeworm and its intermediate host, but since infection with all 

 the common human species, with the exception of the species 

 of Hymenolepis, occurs from eating raw or imperfectly cooked 

 meat of some kind in which the bladderworms have devel- 

 oped, the exclusive use of thoroughly cooked meat is the best 

 preventive measure. Experiments show that pork bladder- 

 worms are killed when heated to 127° F. and beef bladderworms 

 to 120° or even less, but the difficulty of heating the center of a 

 large piece of meat even to this point is shown by the fact that 



