Larger Parasites. 



153 



ing from one-eighteenth to one-sixth iach in length, yet 

 they are among the most deadly worms known. The ma- 

 ture and fertile worm lives in the intestines of animals, the 

 immature in minute cysts ia the muscle. The latter can only 



Fig. 10. 



Fig. 10 — Muscle Trichina encysted, magnified, 

 reach maturity and reproduce their kind when the animal 

 which they infest is devoured by another and they are set 

 free by the digestion of their oysts. When thus introduced 

 into the bowels they grow and propagate their kind, giv- 

 ing rise to much irritation for the first fortnight, diarrhwa, 

 enteritis ox peritonitis. The symptoms caused by their bor- 

 ing through the bowels and into the muscles last from the 

 eighth to the fiftieth day. There are violent muscular 

 pains like rheumatism but not affecting the joints, a stiff, 

 semiflexed condition of the limbs and sometimes sweUings 

 on the skin. In man the affection is often mistaken for 

 rheumatism or typhoid fever, in the lower animals the 

 symptoms are usually less marked but are the same in kind. 

 There are loss of appetite, indisposition to move, pain 

 when handled and stiffness behind. If the patient sur- 

 vives six weeks recovery may be expected because the 

 worms no longer irritate after becoming encysted in the 

 muscle. 



Treatment. In the first six weeks, but especially for the 

 first fortnight, use laxatives and vermifuges. Glycerine, 

 benzine, Diippel's animal oil, chloroform, alcohol and pic- 

 ric acid are fatal to them in about the order named. 



Preventicm. Never eat underdone meat. Trichiua sur- 



