PART III.] Genej'ic Connection of the Cysts with Tape- Worms. 493 



These ova are distributed in various ways ; some find their way into the intestines 

 of the animals adapted to their development j here the ova become ruptured, and 

 the embryo which each contains escapes into the intestinal canal. Now the embryo 

 is provided with six very minute hooks (not always observable through the " shell " 

 of the &gg, and not visible in the particular samples photographed, " possibly the 

 samples were young), two in front and two on either side, by which means they 

 are enabled to bore or burrow their way through the intestinal walls, and pass on 

 into the various tissues of the animal, somewhat after the manner of a mole, the 

 anterior pair of hooks acting the part of the snout and the lateral pairs that of the 

 fore-legs ; * the particular tissue selected depending on the particular species of parasite. 

 Those affecting cattle and pigs lodge themselves between the fibres of muscular tissue, 

 while those of rabbits generally select the peritoneal membrane, and those of sheep 

 are found on the surface of the brain, giving rise, in them, to the disease called 

 " stagge rs." 



The embryo having thus lodged itself, enters on the second stage of its existence, 

 the encysted stage, which, in the case of the species found in cattle and swine, 

 constitutes what is termed " measles." 



This has been over and over again proved by experiment as follows : — ova-containing 

 segments of the Taenia affecting the human subject have been administered to young pigs 

 and calves1[ in some suitable fluid, such as milk and gruel, and when the animals were 

 slaughtered, after a period of from two to three months, the flesh of the greater 

 number has been found thoroughly measled, while evidence of the commencement 

 of this condition may be detected in a fortnight or three weeks. 



As before stated, the bladder-worm in beef and pork presents the same appearance 

 to the naked eye. On separation of the muscular fibres in which the parasite has 

 lodged itself, a tough little fibrous bag may be pinched up with the forceps. This 

 constitutes the "cyst" which has been formed around the worm, and is probably 

 derived from the fibrous tissue or sarcolemma of the muscle with which it is micro- 

 scopically identical. This little sac is firmly attached to the flesh, and cannot be 

 removed except by tearing it away from the latter. On carefully snipping off one 

 of the ends of this fibrous bag and gently pressing it with the point of the finger, 

 another little bladder of a much more delicate appearance, with a shining surface, 



those now presented ; this method of illustrating microscopic objects having of late become of great import- 

 ance, as by the new heliotype-process, permanmt reproductions are obtainable in every way equal to the 

 originals, and at less expense than engraving. 



This process is, I understand, being at present perfected and adapted for India by Captain Waterhouse, 

 Assistant Surveyor General. 



(Since the submission of this Report, it has however been found that the arrangements are not yet 

 sufficiently matured to ensure the supply of a sufficient number of copies within a given time ; they have 

 therefore been very carefully lithographed at the Office of the Surveyor General under the superintendence 

 of Captain Waterhouse.) 



* P. J. Van Beneden, " AJemoirc .svr lex vers -mtestinaux." 



f It is a remarkable circumstance that, as far as is hitherto known, pigs over a year old and grown up 

 cattle cannot be infected ; with young pigs and calves only have infection experiments proved successful 



