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pricked one of the vesicles with a needle, the water spirted out, as out 

 of a fountain. I observed, however, that the distended vesicles con- 

 tained nothing beyond a mere lymph and possessed no special internal 

 vesicle. In separating the one portion of the liver I could not avoid 

 damaging some of the vesicles contained in its interior. Out of these 

 tolerably hard leathery external vesicles, fell bluish, callous (kallose), 

 internal vesicles, which were still closed. In their substance indeed 

 they were somewhat softer than the outer vesicle ; but still far more 

 cartilaginous than the vesicles of the globular, many-headed bladder- 

 worms. On opening these there was found internally in different 

 places a greyish granular matter like the smallest fish roe, which was 

 united to a very delicate mucous membrane, [which] in water however 

 immediately disappeared, so that the granules swam about by them- 

 selves. In a vesicle as large as a dove's egg there were thousands, 

 so small that they could hardly be distinguished by the naked eye. 

 Under No. 4. Tub. A of my microscope I could already perceive the 

 organization of these corpuscles. Their form varied greatly ; some- 

 times heart-shaped with an indent above and a dark line ; sometimes 

 pitcher-shaped, with two round knobs above, at each side one ; some- 

 times like a horse-shoe with a short dark middle line ; sometimes like 

 a rounded handle, with an indent above and with two knobs laterally, 

 and anteriorly rounded oif with a dark circlet. When I used No. 1. 

 Tub. A, I saw clearly that they were true tape-worms. The body flat 

 with dark dots ; anteriorly four suckers, and on the obtusely rounded 

 proboscis, the double circlet of excessively small hooks ; behind, how- 

 ever, in each there was a small excavated indentation like an anus. The 

 others were contracted in quite peculiar forms, and the dark median 

 streak was the hook circlet. Under the compressor, the four suckers, 

 the circlet of hooks and the points become much clearer. In these 

 worms I have observed a circumstance which I have perceived in no 

 other kind of bladder-worm ; namely that on pressure the delicate 

 hooks are detached and float about freely. 



" This kind of bladder-worm is distinguished then from that inhabit- 

 ing the brain of staggering sheep by the following circumstances : — 



" 1. That the vesicles with the granular matter or with many thou- 

 sand infinitely small worms, are covered by a strong leathery external 

 vesicle in which they lie free. 



•' 2. That their roe-like material swims about in the inner vesicle 

 in a clear lymph, and the single worms are only united together by 

 a delicate mucous membrane, but are not as in those, essentially 

 adherent to the bladder, and not even to their [own] membrane. 



" 3. That each of these granules or worms is several hundred times 

 smaller than one of the white corpuscles or worms in the central 

 bladder of the staggering sheep. 



" This is then the same, but now explained phsenomenon, which the 

 acute Pallas has already observed ; but has left without elucidation. 



" In the 'Stralsund Magazine,' 1. St. p. 81, he has already directed 

 the attention of observers to these points : 



" ' Whoso will consider the above description of the true bladder- 

 worm, will not perhaps with M. de Haen deny to worms all partici- 



