METAMORPHOSIS OF THE BLADDER-WORM. 513 



took place fifty-one hours afterwards, and was thus postponed some- 

 what longer than usual. I was at first afraid that the experiment 

 was to have only a negative result, but in the terminal portion of the 

 small intestine I found twelve young tape- worms close beside one 

 another. Their relation to, or rather origin from, the bladder-worm 

 introduced, was proved by the nature of their hooks. With one ex- 

 ception (Fig. 287), they were all of the same character small club- 

 shaped worms, scarcely 1*5 mm, long, which exhibited lively move- 

 ments till they became cold. On microscopic examination it was 

 seen that these worms (Fig. 288) represented essentially only the 

 former head of the bladder- worm. The body, 10 to 12 mm. long, 

 which formerly adhered to the head, was lost, all except the short, 

 thin neck. The former, therefore, does not become a part of the 

 future tape-worm in Cysticercus celluloses, any more than in Cysticercus 

 pisiformis or Cysticercus fasciolaris. Only the neck remains as a 

 stalk or stumpy process, connected with the spherical head, which it 

 nearly equals in length but falls far short of in breadth. A small, 

 half-macerated, ragged appendage to the neck is all that remains of 

 the formerly conspicuous body of the worm. 



FIG. 287. Bladder-worm from FIG. 288. Head of Tcenia solium from the 



the pig, after the digestion of the intestine of a rabbit, in different stages of motion, 

 bladder, (x 20.) ( x 25.) 



To the above there was one exception (Fig. 287). This still re- 

 tained a portion of the former body of the worm. The greater part 

 was lost, and the remainder was rapidly going, but it was still large 

 enough to make this one triple the size of the others. 



The result was, as we have said, in entire harmony with the results 

 of our investigations of other cystic tape-worms ; one fact was, however, 

 striking that the development had not progressed further in the two 

 days which had elapsed since the introduction of the bladder-worms. 

 In the tape-worms of the dog the above-described state is found twelve 

 to fifteen hours after feeding. At the end of the second day they 

 show a distinct segmentation on the considerably elongated body. 



2K 



