TRANSMIGRATIONS AND METAMORPHOSES. 217 



and his children regularly ate, at their second breakfast, 

 raw beef, but one day they took pork instead, and eight 

 weeks afterwards one of the children, when in the bath, 

 voided two ells of Tmnia solium. 



The etiology and prophylaxis of the solitary worm, 

 that is to say, its mode of introduction, and the means of 

 protecting ourselves from it, are clearly indicated. It is 

 sufficient to introduce one of these vesicles into the 

 stomach in order to have the tape-worm. The experi- 

 ment has been made : young men have ventured, in the 

 interests of science, to swallow some, and have ascertained 

 how many days were required for the parasite to be 

 sufficiently complete to give off segments with the feces. 



These vesicles in pork come from the eggs which the 

 taenia has scattered in its passage, and if the pig comes 

 by chance in contact with the fecal matter of a person 

 infested by one of these worms, it is soon infested and 

 becomeB what is' called measled; in this fecal matter 

 there are either free eggs which have been evacuated by 

 the worm, or else fragments, known long since under the 

 name of. cucumerinae, which are full of eggs. 



These fragments of taenia, which I have proposed to 

 name proglottides, and which are nothing else than the 

 worm in all its sexual maturity, are still living and 

 wriggling at the moment of their evacuation, or else they 

 are dead and often completely dried ; but in either case, 

 they are full of eggs. Each egg is surrounded by mem- 

 branes and shells, which effectually protect it against all 

 dangerous contact. 



A fragment of the mature tsenia, thus filled with eggs, 

 when introduced into the stomach of the pig, is rapidly 

 digested, and the eggs are set at liberty. These lose 



