LOSS OF THE CAUDAL BLADDER. 381 



By their experiments, which were mostly made with genuine bladder- 

 worms, and especially with Cysticercus pisifo^-mis of the rabbit, we 

 know that the separation of the bladder begins very soon after the 

 transference of the bladder-worms into their final host, and is complete 

 when they have passed (in about five or six hours) from the stomach 

 to the small intestine, where the now evaginated head becomes fixed 

 by its attaching organs. As to the nature of the process there can be 

 little doubt. The separation is an actual digestion which has natu- 

 rally its first and greatest effect on the caudal bladder, since this pre- 

 sents so large a surface to the action of the digestive juices. This can 

 take place even outside the living organism, as I have elsewhere 

 shown, 1 for the process may be induced by an artificial digestion. Tor 

 this purpose I used the fresh stomach of a dog, into which 1 trans- 

 ferred the bladder-worms, and then exposed it to the warm moisture 

 of an incubating apparatus. 



The experiment is not without interest, since it enables us to 

 watch the worms in the full possession of their vitality. As a rule 

 the bladder-worms appear as extremely sluggish creatures with hardly 

 perceptible motion. But when the 

 moist warmth acts upon them, one 

 notices a lively peristalsis in the 

 bladder, and a protrusion of the body, 

 and can often observe the head pushed 

 out, feeling in all directions, and 

 may even notice how the suckers and 

 the apicial rostellum extend themselves 

 hke tentacles, and then again retract. J^' Jf -^-^,, "^r^^:^ 



The same phenomena may be various phases of motion, (x 25.) 

 observed on the isolated bladder-worm heads, when one takes them 

 from the intestine of a newly killed animal (Fig. 223). They persist 

 until the loss of warmth puts a stop to the lively motions. 



After the digestion of the bladder in the stomach of the animals 

 under experiment, that is to say, after the lapse of about five hours, 

 only the cylindrical body and the head are left. The latter is usually 

 not stretched out until the worm passes to the small intestine ; adher- 

 ing to the posterior end of the body of the worm, one usually finds a 

 few half-digested remains of the caudal bladder. 



Hitherto it has been commonly believed that this body, after the 

 loss of its adherent shreds, passed directly, by solidification and joint- 

 ing, into the future tape- worm body.* ' In the first edition of this 



' "BlasenbandwUnner," &o , p. 156. 



" According to Kiiohenmeister ("Parasiten," 2d ed., pp. 72 and 96) this worm body. 

 (= "Brutkapsel," KUch.) furnishes only the " primary terminal joint of the colony." 



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