THE TAPE-WORM DEVELOPED FROM THE BLADDER-WORM. 495 



but the gradual progress of the development in proportion to the 

 duration of the experiment admits of only one interpretation. 



Nor is even this consideration necessary to refute this objection. 

 The validity of the experiments is obvious. Shortly after the com- 

 mencement of one of my experiments, I was directly convinced of 

 the absence of bladder-worms in two of the animals. And some 

 weeks later the muscles were inhabited by thousands of young 

 bladder-worms. In view of these facts, could there possibly be any 

 doubt ? 



The differences in the number of resulting bladder-worms do not, 

 of course, affect our conclusions ; nor do a few negative results. 

 They only prove that the development of the tape-worms, as of other 

 Helminths (p. 85), is determined by certain conditions, which are 

 differently expressed in different animals. Even where the bladder- 

 worms were most numerous, only a few of the introduced eggs had 

 reached maturity. The pig with 12,000 bladder- worms had eaten 

 three tape-worms. If we allow each of these sixty ripe joints, and 

 take the space containing eggs at 6 cub. mm., then the total number 

 of eggs (which have a diameter of 0*06 mm.) cannot have been less 

 than a million, of which only about 12,000, .or about 1 in 100, 

 reached maturity. A single tape-worm joint might theoretically 

 produce about the half of those 12,000 bladder-worms ! 



It must at present remain undecided whether Gerlach's report be 

 correct or not, that only young pigs are capable of infection. He 

 asserts that at an age of six to nine months feeding experiments 

 always fail. 1 



The experimental proof of the specific identity of Tcenia solium 

 and Cysticercus celluloses is furnished not only by the rearing of bladder- 

 worms, but also by the metamorphosis of the latter into the tape- 

 worm. 2 



Kiichenmeister made an experiment in which, through the prison 

 medical officer, seventy-five pieces of bladder-worm from the pig were 

 given to a condemned criminal during the last three days of his life. 

 They were concealed partly in cooled soup and partly in sausage. 

 Some days before, for want of Cysticercus celluloses, a C. tenuicollis ami 

 six pieces of Cysticercus pisiformis had been given to the criminal. 

 When the corpse was examined forty-eight hours after death, ten 

 young Tcenice, mostly 3'4 mm. long (with one of 6'8 mm.), were 

 found in the small intestine. By the nature of the posterior part of 

 their body, they showed distinctly that they had just left their cystic 

 state. Unfortunately only four of these young tape-worms were 



1 Loc. cit., p. 67. 



2 Wiener mcd. Wochenschr., No. L, 1885. 



