ANIMAL PARASITES. 139 



Is found principally among the very poor. When many 

 worms are present they may give rise to severe symp- 

 toms, and may even be a cause of death. The adult 

 worm only measures from 10 to 15 millimeters in length. 

 The head is provided with four suckers, and also with 

 a single row of booklets. 



VISCERAL CESTODES. 



Whereas adult cestodes which inhabit the alimentary 

 tract occasion as a rule unimportant symptoms, local- 

 ization in various organs of the ''measles" or bladder- 

 worms may be a very serious event. Fortunately 

 man may act as host for the larval forms of only two 

 tape- worms, viz., Tcenia solium and Tcenia echinococ- 

 cus; and more fortunate still, such infestment is not 

 common. 



Or ''measles," it will be remembered, is 

 the embryo stage of Tcenia solium or pork 



tape- worm. Man usually harbors the adult 

 Cellulosa. ^ . -'. . . 



parasite, but from the mgestion of ripe 



eggs he may also become the host of the 

 larvae. The symptoms of infestment depend on the 

 localization of the cysticerci. Unless a vital organ is 

 involved they may be trivial; but in the brain, cord, or 

 eye, serious mischief results. In a few cases the pres- 

 ence of subcutaneous nodules excited suspicion, which 

 was confirmed by removing one and examining with the 

 microscope. 



