PARASITES. 57 



is only caused by pigs having access to human excrement, or 

 to places near privies, etc., from which the segments of the 

 human tape-worm may travel. The cysts, respectively about 



Fig. 5,— Cysticercus Cellulosa, magnified, 



the size of a grain of barley, are found in the muscles, in the 

 loose connective tissue between them and under the skin, in 

 the serous membranes, in the eye, under the tongue, in the 

 brain, etc., of swine. They are also found in this undeveloped 

 form in the muscles, brain, etc., of man, causing disease and 

 death. To man the parasite is usually conveyed by eating 

 underdone pork, or in the cystic form he receives it as the egg 

 in his food (salads, etc.), and water. 



Symptoms. — In pigs the cysts can usually be seen under the 

 tongue or in the eye. In man there are the general symptoms 

 of intestinal worms and the passage of the ripe segments. 

 Other symptoms may attend the presence of the cysts accord- 

 ing to the organ which they invade. Thus when passing into 

 the muscles there are pains and stiffness resembling rheumatism, 

 when into the brain, coma, stupor, imbecility, delirium, but 

 when they have once become encysted they may continue thus 

 indefinitely without further injury. 



Treatment. — The cysts scattered through the body are beyond 

 the reach of medicine. 



Prevention. — Human beings harbouring tape-worms should 

 be compelled to take measures to expel them. Their stools 

 should be burned or treated with strong mineral acids. Swine 

 should be kept far apart from all deposits of human excrement ; 

 no such manure should be used as a top-dressing on pastures 

 open to swine, or on land (market gardens, orchards, etc.) 



