AXIMAL AND VEGETABLE PARASITES. 537 



which soon becomes transversely wrinkled, and afterward divided 

 into distinct rectangular pieces or " articulations." These articula- 

 tions multiply by a process of successive growth or budding, from 

 the wrinkled portion of the neck ; and are constantly removed farther 

 and farther from their point of origin by new ones formed behind 

 them. As they gradually descend, by the process of growth, 

 farther down the body of the tapeworm, they become larger and 

 begin to exhibit a sexual apparatus, developed in their interior. 

 In each fully formed articulation there are contained both male 

 and female organs of generation ; and the mature eggs, which are 

 produced in great numbers, are thrown off together with the articu- 

 lation itself from the lower extremity of the tapeworm. Since the 

 articulations are successively produced, as we have mentioned above, 

 by budding from the neck and the back part of the head, the para- 

 site cannot be effectually dislodged by taking away any portion of 

 the body, however large ; since it is subsequently reproduced from 

 the head, and continues its growth as before. But if the head itself 

 be removed from the intestine, no further reproduction of the articu- 

 lations can take place. 



The Cysticercus is an encysted parasite, different varieties of which 

 are found in the liver, the peritoneum, and the meshes of the areolar 

 tissue in various parts of the body. It consists (Fig. 172) first, of 

 a globular sac, or cyst (a), which is not adherent to the tissues of 

 the organ in which the parasite is found, but may be easily sepa- 



Fig. 172. Fig. 173. 



CYSTICERCCS. a. External cyst, ft In- 

 ternal we, containing fluid, c. Narrow c.v ;il, 

 formed hy involution of walls of sac. at the 

 bottom of which in the head of the tzenia. 



CTBT1CKBC08, nnfoldeJ. 



rated from them. In its interior is found another sac (k), lying 

 loose in the cavity of the former, and filled with a serous fluid. 

 This second sac presents, at one point upon its surface, a puckered 

 depression, leading into a long, narrow canal (c). This canal, which 



