236 



MANUAL OF ZOOLOGY. 



group of Echinococcus heads (fig. 115, B), or it may produce 

 numerous secondary cysts, which may repeat the process, and 

 all of which may incessantly produce " brood-capsules " and 



Fig. 115. A, Sexually mature Ttenia echinococcus, showing the head with its hooklets 

 and suckers, and the three succeeding proglottides, the last containing the reproduc- 

 tive organs (enlarged) ; o Ovary ; v Water- vessels. B, Interior of a portion of a hydatid 

 cyst, showing the brood-capsules and included Echinococci (from Man). C, Young 

 Echinococcus, about six weeks old, showing the thick laminated outer capsule and 

 the inner granular contents. D, Single Echinococcus (from Man), showing the hook- 

 lets, suckers, contained "calcareous corpuscles," and pedicle. All the figures are 

 enlarged. (After Spencer Cobbold and Wilson.) 



" Echinococci." The disease known as " hydatids " in the 

 human subject is, therefore, indicated by the presence in the 

 liver or other solid organ of a strong membranous cyst, often 

 of large dimensions, filled with a transparent watery fluid, and 

 having attached to its interior innumerable minute secondary 

 " scolices," or " brood-capsules," or containing daughter cysts 

 produced by a peculiar form of gemmation. In some coun- 

 tries, as in Iceland, the disease is very common, and it is of a 

 very serious character, as the growth of the tumour is apt to 

 gravely interfere with the vital functions, or even to produce 

 fatal results. The symptoms, of course, depend upon the 

 position occupied by the cyst, and the importance to life of the 

 organ affected. 



