CYSTICERCUS DISEASE OF THE PIG, 



75 



common in those roaming at liber t}' 

 to discover human excrement and 

 the embryos of taenia. The eggs 

 having been swallowed, the six- 

 hooked embryos are set at liberty 

 in the intestine, perforate the 

 tissues, enter the vessels, and are 

 carried by the blood into all parts 

 of the body. Those alone develop 

 well which reach the interstitial and 

 intermuscular connective tissue. 

 The others in the viscera usually 

 disappear. Their presence in the 

 .depths of the muscles produces 

 slight general disturbance and 

 signs of local irritation, due to 

 the development of the cyst itself. 

 At the end of a month the little 

 vesicle is large enough to be visible 

 to the naked eye ; in forty to forty- 

 five days it is as large as a mustard 

 seed, and in two months as a grain 

 of barley. Its commonest seats are 

 the abdominal muscles, muscular 

 portions of the diaphragm, the 

 psoas, tongue, heart, the muscles 

 of mastication, intercostal and cer- 

 vical muscles, the adductors of the 

 hind legs, and the pectorals. 



Symptoms. The symptoms of 

 invasion are so little marked as 

 usually to pass undetected. Occa- 

 sionally, when large quantities 

 have been ingested, signs of en- 

 teritis may occur, but these are 

 generally ascribed to some entirely 

 different cause. In some cases there 

 is difficulty in moving, and the grunt 

 may be altered. 



Certain authors declare that 

 the thorax is depressed between 

 the front limbs, but this symj^tom 

 is of no particular vaUie, and is 



because tliey are mucli more likely 



M 



Fig .5'2. -Se\ei.il poitioiis ot .m adult 

 porlv-iiieasie tapeworm (Tccnia soltinn), 

 natural size. (Stiles, Report U.S.A. 

 BureaiT of Agriculture, 1901.) 



