202 ON THE ANATOMY OF ECHINOCOCCUS VETERINORUM 



The movements of the Echinococci, so far as I witnessed them^ 

 were confined to slow, undulatory, peristahic contractions. I found 

 numbers in every stage of contraction, but I could not observe any 

 actually performing the process. The head with the hooks, is drawn 

 in first, as one meets with many forms in which the suckers only 

 protrude at the extremity, like four knobs. The suckers then follow 

 and are turned completely in, so that their proper outer surfaces look 

 towards one another, the coronet of hooks lying beneath them. In 

 this state, which has been so often described, the animal has not 

 more than half its previous length, and takes on a great variety of 

 forms, oval, rounded, heart-shaped, &c. Instances of these varieties 

 are figured in both plates. 



h. Tlie secondary cysts. — When the fluid contained within one of 

 the large Echinococciis-cysts is emptied into a glass vessel, it is at first 

 turbid with minute white bodies, but these rapidly subside and form a 

 white sediment at the bottom of the vessel. These white bodies vary 

 in size from Tr\j-th of an inch in diameter downwards to xTir'^h- They 

 are the secondary cysts. 



Under the microscope these bodies are seen to be delicate sphe- 

 roidal sacs, containing Echinococci. The largest examined (PI. XXIX. 

 [Plate 22] fig. 9) had at least thirty of these in its interior. It con- 

 sisted of a very transparent structureless membrane, apparently lined 

 by a delicate granular film, which was most distinct near the pedicles 

 of the contained Echinococci. These Echinococci in fact were not free 

 like those contained in the primary cyst, which I have previously de- 

 scribed, but each was attached by a delicate cord, more or less resem- 

 bling the " appendage " of the free Echinococciis, to the inner wall of 

 the secondary cyst (PI. XXIX. [Plate 22] fig. 8), and radiated thence 

 inwards. These Echinococci resembled in all respects those previously 

 described, except that I could observe no ciliary motion in them^ ; 

 they were in all conditions of protraction or retraction, and exhibited 

 the ordinary movements. None were ever found free in a secondary 

 cyst, and the members of each cyst, as well as those in different 

 cysts, were as nearly as may be of the same size and degree of 

 perfection. 



The space left between them in the interior of the secondary cysts 

 was sometimes filled with a clear fluid, and at others more or less 

 obscured by granules. In none of those observed by me was there 

 any trace of the peculiar mode of development of the contained Echi- 



^ This may well arise from my not having examined them till the 28th. Lebert appears 

 to have found the observation of the cilia to be favoured by the interposed membrane of the 

 secondary cyst (vide infra). 



