PARASITES OF ANIMALS. 73 



taiued embryos, which are very different from both the old 

 worm and the measle-worm. They arc provided with six 

 hooks or spines, placed in three pairs upon the head. By 

 means of these they quickly bore their way through the walls 

 of the intestine into the blood-vessels, and are thus carried to 

 all parts of the l3ody. They finally lodge in various organs, 

 but especially in the muscles, liver, brain, eyes, lungs, and 

 heart. They then excavate galleries for themselves in these 

 situations, causing, if in large numbers, a great amount of 

 inflammation and disease, which in some cases proves fatal. 

 The inflammation soon causes cysts to be formed around the 

 intruders, by which tbey are enclosed and restricted in their 

 motions. Thus the " measles" in the muscles of hogs and 

 man are formed. After this the patient may recover, unless 

 these parasites have lodged in the brain or other vital organs, so 

 as to produce serious symptoms subsequently. In the human 

 subject more than 100 cases have been recorded in which 

 these parasites have taken up their abode in the brain, causing 

 epilepsy, insanity, and sometimes sudden death. In such 

 cases, which are probably more common than is generally im- 

 agined, there can be no relief. There have also been recorded 

 quite as many instances in which these c^/5^5^cer(?^ or larval tape- 

 worms have been situated within the ball of the eye, causing 

 a partial or total loss of sight, and sometimes great inflamma- 

 tion. Many of these have been successfully removed. In 

 other important organs they are liable to produce serious 

 trouble. But when in the subcutaneous, areolar, or inter- 

 muscular tissues, they may often be easily removed by the 

 surgeon. In hogs they are much more liable to produce these 

 results, because hogs are likely to swallow whole joints, or 

 even entire tape-worms, while human beings seldom swallow 

 more than a few dozens of eggs. 



The effects and symptoms caused by the adult tape-worms 

 are discussed under the next species, together with the 

 remedies. 



As means of prevention every one should avoid eating pork, 

 in any form, that has not been thoroughly cooked. In this 

 way it is easy to avoid the mature tape-worm of this species. 

 10 



