22 ENTOZOA FOUND IN MAN. 



to that of the tcenia crassicollis of the cat ; or 

 again, that of the cysticercus cellulosce to that of 

 the tcenia solium ; and partly, by experiments which 

 have consisted in causing animals to swallow the 

 vesicular worms which, for some reason or other, are 

 supposed to be the larvae of these taeniae. These 

 experiments, which are deeply interesting, generally 

 offer, nevertheless, much room for error in the very 

 common existence of cestoid worms in the animals 

 which are experimented upon. The opposite experi- 

 ment which consists in making animals swallow the 

 ova of the taenia of another animal, with a view to 

 the production in them of vesicular worms, has been 

 also tried, and may, to some extent, serve as a means 

 of corroborating the results of the other form of 

 experimentation ; but in these, as in the other experi- 

 ments, it is scarcely possible to ascertain decisively 

 if the animals are not already affected by worms 

 similar to those which it is sought to communicate 

 to them. 



Tcenia found in Man (Twnia Solium). 



Variety, or Species A . Tcenia Armata. 



In this worm the strobile is from 20 to 25 feet in 

 length, and, in some instances, the length may reach 

 to as many or even more yards ; the strobile is 

 composed of perishable articulations, or rings (the 

 cucurbitini, or proglottides) ; the posterior rings are 

 quadrangular and oblong in shape, and increase in 

 length in proportion to their distance from the head ; 

 the head (scolex) is furnished with four suckers, and 

 with two circlets of hooks. 



