TENACITY OF LIFE OF THE BLADDER- WOEM. 483 



not merely by the turbid appearance of the bladder-worms, but per- 

 haps still more convincingly by the fact that when swallowed (in 

 three cases) they were found to have no effect. 



The bladder-worms survived the death of their host only fourteen 

 days (in March) ; for after the expiration of this time (and sooner in 

 the parts more exposed to putrefaction, such as the tongue), the para- 

 sites were all found to be dead. If abundantly sprinkled with water, 

 or dipped in it, they perished in twenty-four hours. A solution of 

 common salt had the same effect, so that the supposition that salt 

 meat might sometimes cause infection with Tcenia saginata seems 

 somewhat doubtful. Further, the usual way of preparing beef in Italy 

 has at least the effect of completely killing the bladder-worms. A 

 case is mentioned by Perroncito of forty-six persons (ten families, 

 including children and adults, men and women) who twice ate bladder- 

 worms in flesh prepared in the national way, and yet without any 

 individual becoming infected with tape-worm. 



On the other hand, a student of Perroncito's who had swallowed a 

 newly extracted living Cysticercus, saw the first proglottides leave him 

 fifty-four days later. Fourteen days afterwards he voided, in conse- 

 quence of an anthelminthic which he had taken, a Tcenia saginata of 

 427*4 cm., the number of whose joints was estimated (from below 

 the neck) at 866. 



The experiment just mentioned is, however, neither the first nor 

 the only one, directly proving the development of the bladder -worm 

 into Tcenia saginata. Oliver, an Indian army surgeon, had previously 

 subjected a Mohammedan and a Hindu boy to the same experiment, 

 and, twelve weeks after the swallowing of the bladder-worm, obtained 

 from both the proglottides of Tcenia saginata. 



It is thus clearly shown by the foregoing observations, the only 

 ones that state with any definiteness the term of the infection 

 that from nine to twelve weeks must elapse before the Tcenia saginata 

 gives off the first proglottides. The regeneration will, of course, take 

 a longer or shorter time, in proportion to the size of the remaining 

 neck. If the head be left behind, we generally expect that proglot- 

 tides will be again voided, in two to two and a half months after the 

 first expulsion. Cobbold reports a case in which medicine was ad- 

 ministered three times in succession, whose first application had the 

 effect of expelling a stretch of joints 14 feet in length. On being 

 repeated ten weeks later, 16 feet were voided, and a third dose, nine 

 weeks after the second exit of proglottides, evacuated a stretch of 

 17 feet. Schimper estimates the average number of proglottides 

 voided in one day at eight to twelve, but this varies greatly, and is 

 often not so large (p. 477). The exit of a larger number (Kiichen- 



