Zoological Society. 389 



frequently in abnormal cavities in the liver — are caused by a worm 

 similar to, if not identical with, our bladder-worm, I say from a worm 

 ■probably resembling our bladder-worm ; for we find in the liver and 

 lungs of Oxen and Sheep another wonderful kind of watery bladder, 

 which seems to arise from nothing but some kind of animal germ ; 

 but however is widely different from our bladder- worm, and cannot 

 have arisen from it.' " 



Pallas, after describing some of the Hydatids, goes on to say : 



" The water-bladder itself consists of a white, hardish, quite ho- 

 mogeneous membrane, which becomes thinner towards the caudal 

 extremity ; wherever it is lacerated it folds back, and may be best 

 compared with a section (as thin as paper) of a boiled cartilage of a 

 young animal. Within, this external strong membrane is lined by a 

 delicate structure or membrane, which is very easily separated from it, 

 and is beset with a great number of small, white, commonly round, or 

 oval, corpuscles. The corpuscles consist, as the microscope shows, of 

 longish globules united together, whose substance appears to bedotted." 



Subsequently (p. 261) Goeze quotes from the 'Nordische Beytrage,' 

 1. St. p. 83, thus: 



" It is probable that the unattached hydatids which are at times 

 observed in the human body (are), either of the same kind as the proper 

 bladder-tape worm, or are the same as those singular watery bladders, 

 which I have observed and described in the liver and lungs of diseased 

 Calves and Sheep, and which are most certainly also to be ascribed 

 to a living creature, and are not indistinctly organized (at least if we 

 consider the inner membrane strewed over with granular globules). 



"On reading through Leake's treatise upon the ' Staggers in the 

 Sheep,' p. 85, it seems very probable to me that the bladders in the 

 brain are more similar to those which I have described in the lung 

 and liver in Sheep and Calves, than to the bladder-worm which Ty- 

 son and Hartman have described before me (our globular one) ; nay 

 perhaps, that they even constitute one genus with the former. The 

 small worm provided with a circlet of hooks and four suckers, in these 

 vesicles, might be a development of the globules observed by me. 



" I have at present no opportunity of examining these vesicles in 

 the fresh state. Perhaps on applying a stronger magnifying power 

 the granules might exhibit more organization. 



" Consequently, Pallas did not at that time know what to make out 

 of the granules of these vesicles. The peculiar organization of these 

 he did not himself see, as I have now discovered, described and 

 figured it. To whom then belongs the first and true discovery of 

 the nature of the granules in the internal membranes of the singular 

 Hydatids of the livers and lungs of Calves and Sheep ? 



"But I wish that I could throw more light upon and explain the 

 mode of origin of these vesicles, and upon the ceconomy of the many 

 thousand single worms socially united in a single bladder. Do they 

 grow ? do they disperse themselves 1 does each build its own dwell- 

 ing ? or where do they remain ? shall our successors learn nothing 

 on these matters? " 



Goeze' s figures are very good. 



