IMNIA ECHINOOOCCUS. 



253 



CHAPTER YII. 



T^NIA BOHINOCOCCUS. 



General and specific characters of the Tcenia echinococcus — Grounds for disputing 

 Ktichenmeister's notion that there are two distinct forms of Echinococcus — Struc- 

 ture and development of the adult worm — Hydatids — Exogenous, endogenous, and 

 multilocular varieties — Growth and structure — Formation of the scolices within 

 brood capsules — Opinions of Owen, Wilson, Busk, Huxley, l^aumyn, and Leuckart, 

 severally contrasted. 



I HAVE purposely curtailed my account of the comparatively 

 unimportant cestodes described in the last chapter, in order that I 

 may dwell with more particularity on the only remaining tapeworm, 

 namely, the Tmnia echinococcus. This species, in its larval condi- 

 tion, is probably more injurious to the human race than all the other 

 species of entozoa put together ; or, to say the least, it is more 

 frequently the immediate cause of death than any other internal 

 parasite. Its importance may be realized from the fact that M. 

 Davaine, in his well-known " Traite des Entozoaires," extending 

 over eight hundred pages of letterpress, devotes nearly three hun- 

 dred pages to the consideration of cases illustrative of the so-called 

 hydatid formations. These are the larvae of this cestode. 



17. Tjinia echinococcus. 



T. echinococcus, Von Siebold ; Leuckart. 



T. echinococcus scolicijpariens, Kiichenmeister. 



T. granulosa, Gmelin; Prochaska. 



T. viceralis socialis granulosa, Goeze. 



T. nana, Van Beneden. 



