EXPERIMENTS BY THE METHOD OF FEEDING. 491 



solium, and confirmatory opinions were immediately expressed.^ But 

 his view did not obtain general acceptation until the connection of 

 the two parasites was firmly established on experimental grounds, and 

 that principally by the proof that the eggs of Tfenia solium develop in 

 the pig into the familiar tladder-wonn of the muscles, and also that this 

 is the larval form of the Taenia. 



The first attempt of this kind was made by van Beneden, who 

 fed a pig' with a tape-worm, and four and a half months afterwards 

 found it to contain bladder-worms.'^ No proof was given, however, 

 that ■ these bladder- worms originated from the eggs of the worm 

 'administered, so that the result of the experiment cannot be regarded 

 as completely convincing. But any doubt which might have existed 

 on this point has been entirely removed by the experiments of 

 Haubner and Kiichenmeister. 



Haubner administered^ at different times single proglottides and 

 larger pieces of tape-worm to five young pigs, which came of a brood 

 free from bladder-worms, and succeeded thereby in infecting three of 

 them with bladder-worms. The two other pigs remained uninfected 

 in spite of the feeding ; but this negative result cannot in any way 

 affect the cogency of the argument, since in the three other cases 

 the degree of development of the bladder-worms was proportionate 

 to the period that had elapsed since the feeding. 



The first pig was killed thirty-two days after the first feeding and 

 thirteen days after the last. It harboured in different parts of the 

 body isolated bladder-worms, altogether about fort)' or fifty, the 

 majority being found in the neck. The largest were about the size of 

 a hemp-seed, and showed the first rudiment of the head as a minute 

 opaque spot. 



The second pig was dissected forty-six days after the first and 

 twenty-seven days after the last feeding, and was found to contain 

 several thousand bladder -worms, which were distributed over the 

 whole body,— some of them being as large as a pea, while the smallest 

 were about the size of a hemp-seed. Microscopic investigation 

 revealed in the more advanced bladder-worms a distinctly formed 

 head, with the rudiments of hooks and suckers at various stages of 

 development. The head-process shone through the walls of the 



' I was the first to express myself frankly, and indeed on the ground of my own 

 investigations, in favour of Kiichenmeister's statements. I frequently had heads of 

 different bladder- worms submitted to me by scientific friends for examination and identi- 

 fication, but could never succeed in distinguishing those of Cysticercus celluloses and of 

 T(enia solium from each other, and always regarded them both as heads of the same 

 species, like those of Cysticercus tenuicollis and T. marginata, &o. 



' Ann. sei. nat., t. i., p. lOi, 1854. 



" Gurlt's Magazin fUr Thierarzneilcunde, p. 103, 1855. 



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