A PERSISTENT PARASITE 337 



digest anything else; and the hateful intruder will 

 perish." 



"Not at all. The digestive energies of the stom- 

 ach make no impression on it. It passes through 

 quite untouched, protected perhaps by its resistant 

 shell, and goes farther on to establish itself defini- 

 tively in the intestines. 



"And now all the conditions are the best possible 

 for the worm. The situation is quiet, disturbance 

 from without is not to be apprehended, and the best 

 food in our power to furnish is supplied in abun- 

 dance. With its double ring of hooks, each one 

 shaped like the fluke of an anchor, the organism 

 fastens itself to the wall of its abode and straight- 

 way begins to develop. On its arrival it was a very 

 short and wrinkled little worm, terminating at one 

 end in a small round head, at the other in a spacious 

 bladder. In a short time it will turn into a sort of 

 ribbon that may attain the enormous length of four 

 or five meters." 



' ' Oh, how horrible ! ' ' cried Louis. ' * Can it be that 

 we serve as a dwelling for such a guest 1 ' ' 



"Say rather for a number of such guests, since 

 as a rule they are not found singly. They are com- 

 monly called solitary worms, an improper term, as 

 you see, since there are generally several of them to- 

 gether. Their real name is taenia, or tape-worm, 

 from their ribbon-like form. 



"Imagine a narrow tape or band of a dull white 

 color, a sort of ribbon of variable length that may 

 measure as much as five meters ; imagine this ribbon 



