LATER DEVELOPMENTAL STAGES. 



597 



more than the average size. As in the previous case, the cysts were ex- 

 clusively confined to the interlobular spaces, although their number was 

 much greater, and amounted to at least from 100 to 120. It is remark- 

 able that the cysts were all thickly distributed under the serous covering 

 of the liver, and that upon both the concave and convex surfaces. 



The smaller Echinococci (of 0'5-0'8 mm.) corresponded in structure 

 with those found in the first experiment. The only difference per- 

 ceptible on superficial inspection was that the contents of the zona 

 were appreciably clearer than before. This increase of transparency 

 was due to a partial liquefaction of the contents. The Ecliinococcus, 

 which was formerly a solid mass, had meanwhile become a bladder, 

 which, when pricked, voided a portion of its contents in the form of a 

 transparent fluid, and then collapsed. 



The fluid had collected in the centre of the spherical body, so that 

 below the zona a second membrane could be distinguished, which 

 lay along the inner surface of the latter, and is to be regarded as a 

 membranous expansion of the real body-parenchyma (" germinal mem- 

 brane," Huxley, " Keimhaut," Naunyn). The zona itself appeared as 

 a cuticle, and was distinctly lamellated, as we have already noted in 



FIG. 321. Echinococcus-bl&dder eight weeks old. ( x 50.) 



the adult ^cAmococcws-bladders. But the lamellse were as yet neither 

 very distinct nor sharply defined, although the membrane sometimes 

 attained a thickness of 0'07 mm. The inner membrane closely 

 adjoining the cuticle exhibited, besides the granules formerly pre- 

 sent, some cellular structures, which presented many differences in 



