ACEPHALOCYSTS. 231 



Echinococci, in which a similar structure of the cyst usually 

 occurs only in large colonies, or in those which contain the 

 remains of dead scolices and purulent grumous masses. 



3. Acephalocysts derived from Taenia ex Cysticerco tenuicolli. 

 What Eschricht regarded as possible has since proved to be 

 the case; in one administration of eggs of T. ex Cyst, tenuicolli 

 to a lamb (vide Cysticercus tenuicollis) , I found a sterile Cysti- 

 cercus tenuicollis in the midst of hundreds of other, equal-sized 

 and fully developed Cysticerci of this species. This sterile 

 individual bore perfectly distinct indications of life. I do not 

 know whether other specimens of Cysticercus or Ccenuri have been 

 met with in a living but barren state, but there can be no doubt 

 that this is possible. 



I have seen dead, barren Cysticerci and Coenuri of this kind. 

 These, however, are distinguished from the dead acephalocysts 

 derived from Echinococci ~m that the intimate contact of the cyst 

 and the worm has ceased, and the latter lies collapsed at the 

 bottom of the former; its walls are of a dingy yellow colour; 

 the fluid has escaped from its interior between it and the enve- 

 loping cyst, but sometimes a firm calcareous mass, sometimes 

 a more fatty mass, is deposited upon it in a dense, detachable 

 stratum. If there be a whitish turbid spot, or in the Ccenuri 

 several of these, in one or several parts of the vesicle, forming 

 the indications of the incipient processes of scolex-formation, 

 which was interrupted immediately at its commencement by 

 unknown causes, probably produced by death, we cannot cull 

 these structures acephalocysts, because a proliferation had just 

 commenced. All structures which are really to be called acepha- 

 locysts, and which are living, sterile specimens of Cysticerci and 

 Coenuri, are distinguished from those derived from Echinococci in 

 that the walls of the latter consist of very distinct concentric 

 layers, tremble like jelly, and are extraordinarily elastic, whilst, 

 as I have convinced myself in one living acephalocyst from 

 Cystic, tenuicollis, the walls of the analogous structures derived 

 from Cysticerci are considerably thinner, by no means exhibit the 

 elastic consistence of jelly, and consist of such fine and delicate 

 concentric layers, that indications of them can only be detected 

 by great care and practice. Lastly, the latter exhibit, although 

 but sparingly, a deposition of calcareous corpuscles, in particular 

 spots within their walls, in greater abundance than the Echinococci. 



