156 PAV.ASITOLOGY. 



groups of muscles; the pain lasts only during the 

 migration of the embryos ; after encystment there is no 

 pain. Hogs: — The intestinal form causes diarrhoea ; 

 the migration of the embryos pruritus, rubbing, 

 scratching, stiffness of gait, difficulty in swallowing 

 and mastication, difficult and painful respiration. 

 The disease is usually fatal in man; it is not liable to 

 be fatal in the hog or rat. 



Vitality. — Vermifuges and vermicides have little 

 effect upon them. Degeneration usually destroys 

 the larvae in the cysts in from twelve to eighteen 

 months, although cases are on record where their 

 vitality has lasted much longer. They will live one 

 hundred days in decaying meat. Fourteen degrees 

 below zero. Cent., will kill them. 



Complete salting kills those that are superficial in 

 a short time, but those in the deeper parts live for a 

 long time. Sausage in pickle 15 days destroys them. 

 Sausage in hot smoke kills them in 24 hours, cold 

 smoke 3 days. 



To determine if Trichina are alive two methods 

 can be used. First, feed a small bird the trichinous 

 flesh and kill the bird 8 to 10 hours after; if the 

 trichini are dead they will be digested with the cyst; 

 if they are alive they will be coiled or moving. 

 Second, if a small particle of macerated meat contain- 

 ing the cysts be placed on a platinum plate and heat- 

 ed to a temperature of 100 to 105 degrees Fahrenheit, 

 then noted under the microscope, movement will be 

 seen if they are alive. Thorough cooking destroys 

 them. To destroy the trichina in a ham it should 

 be cooked thirty-five minutes for each two poinds 

 of weight. 



