230 



THE FLUKES 



The full life history of none of these intestinal parasites is 

 known, and we can only guess at them by analogy with more or 

 less closely related parasites about which we have more knowledge. 

 None of them do enough damage to cause more than slight in- 



nat.size. 



FIG. 80. Fasciolopsis buski, a large intestinal fluke of man. X 1\. Abbrevia- 

 tions as in Fig. 74. (After Odhner.) 



testinal irritation or catarrh, and sometimes light dysenteric 

 symptoms. They are susceptible to most of the drugs used for 

 expelling tapeworms and roundworms. Some species are said 

 not to be affected readily by santonin, though they are expelled 

 by thymol and naphthalene, and presumably by oil of chenopo- 

 dium. 



