T^NIA SOLIUM. 217 



tained corpuscles had been previously described by Hessling, who 

 discovered them in the muscular fibres of the heart of the sheep, 

 ox, and roe.* They were regarded by him as granular masses 

 formed by the disintegration or breaking up of the muscular sub- 

 stance, but Leuckart thinks it more probable that they are 

 organized structures comparable to the so-caUed sacs of Psoro- 

 spermise. 



The smallest measles found by Leuckart measured as much as 

 ^" in length, being obtained from the brain, hver, and intermuscu- 

 lar substance of a pig fed with tapeworm proglottides about thirty 

 days previously. Only those specimens, however, occurring in the 

 liver at this early period, displayed an outer membrane proper to 

 the worm itself, the others being simply invested with capsules 

 formed out of the surrounding connective tissues belonging to the 

 host. Many measle masses in the same host were much larger, 

 presenting an average diameter of |". The smallest of the above- 

 mentioned already displayed a smooth, transparent, homogeneous, 

 outer, cuticular membrane, overlying a double, finely-granular 

 corium ; the latter being traversed by a branched system of aquife- 

 rous vessels. These vessels proceed fi:-om a central spot, which 

 marks the position of the so-caUed head-cone or receptaculum 

 capitis. It is, in fact, the first well-marked indication of that 

 flask-shaped capsule within which the head, neck, and body of the 

 Cysticercus is formed, and which Groeze long ago very aptly com- 

 pared to a lantern (Figs. 6 — 10, Plate XII). As growth proceeds, a 

 very interesting series of changes takes place within this cavity, by 

 virtue of which these several parts, as well as their own distinctive 

 organs, are continuously brought into view. A central granular 

 mass forms the true foundation of the head, its upper or stalk-like 

 extension forming the future neck and body. Fm-ther develop- 

 mental changes (into the minuter particulars of which the limits of 

 this work forbid me to enter) successively result in the evolution of 



* Siebold and Kolliker's " Zeitschrift," Bd. v. 1853. See also Leuckart ; s. 240. 



F P 



