WORMS AND CCELENTERATA 28 1 



reach the eye — which has often happened — they 

 cause blindness, and it is still worse if they reach the 

 brain. Hence a man who is infected with Tcsnia 

 solium is in a condition of great danger to himself 

 and those about him, as new infection is very possible. 

 It also happens that in vomiting the sections pass 

 from the intestine into the stomach, and the larvae 

 are set free there. This is a moment of great 

 danger to the patient, as it is always the larva- ■ 

 stage that may cause death ; the adult tape- worm 

 is not dangerous. A man with Tisnia solium 

 should, therefore, get rid of it as soon as 

 possible. 



Still worse are the scolices of the Tcsnia echinococcus. 

 This tape-worm is only one-fifth of an inch in length, 

 and is found in large numbers in the intestines of 

 the dog. The detached parts are very active; they 

 climb up stalks of grass, and are likely to be eaten 

 by hares, as well as by cattle, sheep, or pigs. The 

 larvae that develop pass into the muscles, but before 

 the formation of the head begins, they grow so large 

 and soak up so much fluid that they cause blisters as 

 big as a child's head, which are generally fatal to the 

 victim. The head of the echinococcus does not begin 

 to form until after this swelling. Man may eat these 

 larvae with impunity, as they do not develop into tape- 

 worms in his intestines ; they do so, however, in the 

 dog. But if the eggs of the echinococcus get into the 

 human mouth and stomach — and the dog will often 

 give them an opportunity to do this, as it licks its 

 anus as often as it does the hands (or even the 



