254 THE ANIMAL PARASITES OF MAN 



cuticle and internally by the parenchymatous layer. They 

 originate between the strata of the cuticle of the mother cyst 

 from small, detached portions of its parenchymatous layer ; during 

 their growth they bulge inwardly or outwardly and may separate 

 themselves entirely from their parent cyst. ' In the latter case 

 they lie between the mother cyst and the capsule of con- 

 nective tissue formed by the host (Ech. granulosus or Ech. 

 hydatidosus exogenus) ; when growing inwardly they reach the 

 interior of the mother cyst (Ech. hydatidosus endogenus). Their 

 number is very variable and does not depend on the size of the 

 mother cyst. 



FIG. 179. Echinococcus hominis in the liver, reduced. The fibrous capsule 

 and the wall of the echinococcus have been incised, so that the daughter cysts may 

 be seen. (After Ostertag, from Thoma.) 



The endogenous " daughter cysts " are attributed by some 

 authors to transformed brood capsules and to scolices that have 

 fallen off the mother cyst. However feasible this theory sounds, 

 there can be no doubt that the views of the less recent observers 

 are correct. Sterile mother cysts, however, also occasionally con- 

 tain daughter cysts, and these Naunyn considers to arise from 

 parts of the wall of the mother cyst, constricted off. 



The " daughter cysts " may be constituted like the " mother 

 cysts." that is to say, they may remain sterile, or may produce 

 brood capsules, or again other cysts, which are called " grand- 

 daughter cysts." The mother cyst may perish, so that the cysts 

 then lie in the internal space of the connective tissue capsule. 



