DEVELOPMENT OF CYSTICERCUS. 431 



gradually disappear after they have broken away from the cavity of the 

 sarcolemma, and gained access to the spaces between the muscular fibres. 

 " In this new situation they gradually lose their former membranous 

 clothing studded with cilia-like fibres, which can occasionally be seen 

 partially deprived of its corpuscular contents, though sufficiently perfect 

 to admit of demonstration. The reniform corpuscles before aggregated 

 together in circular groups now gradually lose their distinctness of outline, 

 and imperfectly coalesce into confused ill-defined masses, having an oily 

 aspect, so that, if in this state, one of these verrnicules be crushed under 

 the microscope, amorphous oily and granular matter will be seen to have 

 escaped from it, similar to that contained in the ventral part of the adult 

 animal. Here, too, the restraint to the lateral growth of these entozoa 

 being very much diminished, their breadth increases rapidly, and they 

 present globular projections extending out very irregularly from their 

 sides, giving them an irregular figure. These projections gradually take 

 on the form of those which were described on the ventral part of the 

 perfect entozoon. The largest of the entozoa which I have seen in this 

 stage is about -^th of an inch in length and ^th in breadth. 



" The next facts requiring especial notice are those connected with that 

 stage of development which takes place after the animalcule has become 

 surrounded by an adventitious cyst. 



" The first indication of the formation of such a cyst is, the turgescency 

 of the capillaries, or some of the smaller vessels in the vicinity of one or 

 more entozoa. Granular bodies, exudation-corpuscles, and fibres of 

 different shapes next make their appearance. These at first only partially 

 obscure the entozoon, but afterwards completely conceal it. When the 

 cyst is first formed, the animalcule can, by a good light and careful 

 examination, be obscurely seen within it, and by dissection under the 

 microscope it can be dislodged. 



" The interior of a cyst being smaller than the animalcule contained 

 therein, it naturally follows that during its growth one portion must be 

 folded over another. By this means it is adapted to the confined locality 

 in which it is lodged during the period of its development. Hence the 

 ventral portions of all Cysticerci are, when first taken from their cysts, 

 very much plicated ; but these plicae disappear after the ventral sac has 

 become distended with the fluid brought into contact with its surface. 



" Up to this point of the development of the Cysticercus, it is a simple 

 cyst growing by the assimilation of fluid imbibed equally by every part 

 of its surface, no one part differing sensibly in its structure from another. 

 No portion of this surface presents any indication of incipient booklets or 

 suckers. There is nothing either on its surface or in its interior analogous 

 to the structure of an ovum. Nor is there any other anatomical charac- 

 ter which would raise its organization above that of a simple acephalocyst. 

 However, this so exactly resembles in its structure that of the ventral 

 portion of a perfect Cysticercus, that it is impossible to doubt their 

 identity of character. Its size, too, is not much beneath that stage where 

 the suckers and booklets first begin to present obscure indications of the 

 part they are about to occupy. 



" The first indication of the addition of the neck with the suckers and 

 booklets to the ventral part of a Cysticercus is the appearance about its 

 centre of a slightly raised body, depressed in the middle, with longitudinal 

 folds proceeding from each side of it towards the poles of the ventral cyst, 



