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II. " On the Structure and Development of the Cysticercus 

 cellulosse, as found in the Pig." By GEORGE RAINEY, 

 Esq., Lecturer, and Demonstrator of Practical and Micro- 

 scopical Anatomy at St. Thomas's Hospital. Communi- 

 cated by ROBERT D. THOMSON, M.D., F.R.S. Received 

 June 27, 1855. 



(Abstract.) 



The Cysticercus cellulosae, in its mature state, consists of two 

 parts : one a small oval cyst, composed of a very thin membrane, 

 rendered uneven on its external surface by minute rounded projec- 

 tions, and containing in its interior, granular matter, particles of 

 oil, and a colourless fluid. This may be called its ventral portion. 

 The other is folded inwards, occupying the centre of the cyst just 

 described, but by pressure it may be made to protrude. This part 

 is sometimes called the neck. Its length varies very much in dif- 

 ferent cysticerci, depending upon their age. It is hollow, having 

 strong membranous parietes, wrinkled transversely, and composed 

 both of circular and longitudinal fibres. The cavity has no visible 

 communication with that of the ventral portion. It contains a 

 multitude of small oval laminated calcareous bodies, which, when 

 acted upon by acids, effervesce briskly, and become partially dis- 

 solved, leaving only a small residue of animal matter. When the 

 neck is protruded, the extremity farthest from the cyst is seen to 

 present an enlargement, sometimes called the head, on the free 

 surface of which there is a quadrangular area, occupied by 

 four circular disks and a ring of booklets. Each angle contains a 

 disk, and the booklets are placed in a circle around the centre of 

 this space. The suctorial disks are traversed each by a passage 

 taking rather a spiral course, and terminating in the cavity of the 

 neck. The membrane composing a disk presents two orders of 

 fibres, circular and radiating. The booklets are generally twenty- 

 six in number, thirteen long and as many short, arranged alter- 

 nately a long and a short one. Each consists of a curved portion 

 like a bird's claw, and a straight portion or handle ; and at the 

 junction of these two parts there are tubercles, two in the short 

 booklets, and only one in the long ones. The booklets are crossed 

 by two zones of circular fibres. They are also connected by 



