ORGANS OF LOCOMOTION 143 



of about eleven years, but the capsule and some of the 

 interior of the cyst undergo calcification, the process 

 beginning about one or one and a half years after encap- 

 sulation. 



Swine become infested by eating trichinous flesh of 

 pigs, rats, or other animals, or from eating the excretions 

 of infested animals. All breeds of swine, regardless of 

 age, are equally susceptible. Trichinosis is most preva- 

 lent in swine kept in small pens, especially when sani- 

 tation is not observed. 



Lesions. The adults produce an intestinal catarrh 

 which is most evident in the proximal portion of the in- 

 testine. Soon after the embryos begin to migrate the 

 mesenteric lymphatic glands become enlarged, and there 

 may be pulmonary congestion and parenchymatous 

 degeneration of the liver and kidneys. The affected 

 muscle first becomes swollen, and appears of a gray color. 

 About eight weeks after the embryos begin to migrate, 

 small gray or grayish- white specks may be detected in 

 the muscle tissue. This condition is especially evident 

 in the diaphragm, intercostal muscles, muscles of the 

 cervical region, and tongue. If the lesions are of long 

 standing they will contain calcium salts, which may be 

 detected as small, gritty masses. Microscopically, in 

 the first year of muscular trichinosis the larvae can be 

 readily detected as small, coiled, thread-like worms 

 within a capsule. 



Symptoms. Clinical trichinosis has been observed 

 only in experiments, or at least the disease has not been 

 recognized by the clinician. Experimentally, intestinal 

 trichinosis becomes evident in from three to six days 

 after infestation. The disease is manifested by the 

 following symptoms: inappetence, vomition, diarrhea, 

 colic, arched back, unwillingness to move, and rapid 

 emaciation. Evidence of muscular trichinosis appears 

 in about two weeks, and is manifested by the following 

 symptoms: rubbing against posts or other objects, 

 stiffness, assumption of the lying posture the greater 

 part of the time, dyspnea, dysphagia, and rise of tern- 



