498 DEVELOPMENT AND GROWTH OF T^ENIA SOLIUM. 



could (from his description) be scarcely distinguished from the ordinary 

 bladder-worm of the pig, although my respected friend is inclined to 

 regard this as an example of a yet unknown species the hypothetical 

 Tcenia tenella, Cobbold. 1 Further, an attempt I made to infect the 

 sheep with T. solium had only a negative result. Maddox 2 also de- 

 scribes a hooked Cysticercus from the muscles of the sheep, but regards 

 it not only as a new species, but as a sexually mature animal (Cysti- 

 cercus oviparus). We must, of course, remember that our knowledge 

 of bladder-worms from the muscles is not yet by any means complete, 

 as is evidenced by the above-mentioned (p. 405, note) Tcenia Krabbei, 

 which Moniez reared in the intestine of the dog from the bladder- 

 worms of the reindeer. Under such circumstances, we must leave it 

 undecided whether the bladder-worm from the muscles of the alpaca 

 (which seems to be very frequent in Peru, since the four animals in- 

 vestigated by Sappey were infested to an extraordinary extent 3 ) should 

 be identified with the Cysticercus celluloses, especially since we do not 

 yet know whether or not it is provided with hooks. 



It is quite otherwise with the bladder-worms of the dog, which, 

 according to Leisering's observations,* are distinctly identical with 

 the bladder-worm of the pig, although my attempt to rear them in the 

 dog from the eggs of Tcenia solium was as unsuccessful as my previous 

 attempt in regard to the sheep. In Leisering's case the bladder- 

 worms were found not only in the muscles but also in the lungs and 

 liver. 5 They were distinguished by their unusual size, but in the 

 viscera they were mostly dead and shrivelled up. J. Vogel gave a 

 similar account a long time before of a blind and apathetic dog whose 

 brain was completely penetrated by Cysticerci.* In the cat also I 

 once found a single large Cysticercus celluloses under the right shoulder- 

 blade. 



Development and Groivth of Trenia solium. 



In the above discussion of experimental investigations, we have 

 already had the opportunity of following the developmental history of 

 this tape-worm with some completeness. We know not only the dif- 

 ferent developmental stages which are passed through, but also how 

 these follow one another. The following summary, based largely on 

 my own observations, will show the extent of our knowledge. 



1 Not to be confused with T. tenella, Pall., which belongs to the modern genus Both- 

 rioccphalus. 



Monthly Micr. Journ., vol. ix., p. 245. 

 Comptes rendus Soc. bid., t. ii., p. 178, 1860. 

 Bericht uber das Veterinarwesen Sachsens, p. 18, 1864. 

 " Pathologischische Anatomic," p. 434. 

 Similarly Gerlach, loc. cit,, p, 69. 



