PART III.] Experimental Development of the Tape- Worm. 499 



particles, some of which present a laminated appearance very like a section of 

 " alternating calculi." These are acted on by acids, but even strong alkalies scarcely 

 affect them, and I have failed to detect any great difference in their appearance after 

 subjecting them to the flame of a blow-pipe. They have been mistaken for eggs, 

 but they are very different in appearance from ova, as may be seen by comparing 

 micro-photograph No. 12, Plate XXXVII, representing these particles from a beef 

 measle, magnified by a |^ objective, with No. 3, Plate XXXVI, in which three eggs 

 from a mature tape- worm are represented as well as the calcareous corpuscles (which 

 lie on a lower plane and consequently somewhat out of focus). 



In the cysticercus stage these parasites contain no ova, are sexually immature, 

 and incapable either of further development or of reproducing others of their like, 

 until they find their way into the intestinal canal of the animal which devours the 

 flesh in which they are encysted. 



With the view of ascertaining whether the particular bladder-worms under 

 consideration would develop in other than the human intestines, I have repeatedly 

 administered flesh containing numerous cysts to animals ; nine dogs (three being 

 puppies) have been thus experimented upon, their excreta examined daily until 

 slaughtered at periods varying from a fortnight to three months, but in no case 

 could I satisfy myself that these cysts had left a trace. They were all evidently 

 digested, together with the meat which contained them. Tape-worms there certainly 

 were, but of a very different kind to those found in the human subject, so that 

 the dissemination of the human tape-worm by dogs eating the carcases of pigs and 

 cattle is not probable. With man, however, the case is different, for it has been 

 conclusively proved that, when raw measly pork is eaten, tape- worm (tcenia solium) 

 may be produced. Professor Leuckart, of Giessen, the chief authority on this 

 subject, has actually produced this tape-worm in a prisoner who had been placed 

 at his disposal for the purpose. The evidence is very nearly as conclusive in 

 connection with the beef and veal measle, for Assistant Surgeon Oliver, E.A., has 

 succeeded in producing (in the Punjab) the taenia mediocanellata in two low-caste 

 natives, from whom no previous history of the existence of tape-worm could be 

 obtained ; moreover, the identity of appearance of the head of the mature bookless 

 tape-worm {tcenia Tnediocanellata) with the head of the encysted worm in beef the 

 fact of tape-worm being endemic among the Abyssinians, who do not eat pork, but 

 only the flesh of cattle, and that in the raw state, as well as the fact that the ova 

 procured from the taenia mediocanellata in man have repeatedly produced measles in 

 calves, leave no reasonable doubt on the subject. 



In considering the most practicable methods of reducing the risk of mischief 

 arising from the consumption of meat in localities where measled animals are numerous 

 it is of importance to bear in mind the ages at which the animals are slaughtered in 

 these districts. As already stated, pigs under a year old cannot be infected nor can 

 grown-up cattle, and in connection with the latter class of animals, Cobbold has made 



