72 ANIMAL PARASITES. 



of the Tcenia pass through a true cysticercal (bladder-worm) state, 

 whilst the other part, without ever arriving at this state, furnishes 



grow mouldy. The rapidity and intensity of the result was extraordinarily increased, so 

 that he absolutely regards putridity as a means of assisting the infection. 



As the vertigo always makes its appearance in sheep at a definite time after the 

 administration of Tcenia ccenurus, and with some practice in the experiment, one may 

 previously state pretty exactly in what stage of development and of what size the 

 expected vesicular worms will be found, the experiments on the production of the 

 cystic worms satisfy the requirements of the most rigid analysis ; at least I will bind 

 mvself as regards Ccenurus, Cystic, cellulosce, and Cystic, pisiformis, to determine 

 pretty exactly how large and how far advanced in development these forms will be, 

 after the administration of T. ccenurus, T. solium, and T. serrata. As regards" the 

 experiments in the administration of T. crassicollis to mice, I have never, like 

 Leuckart, been able to rear Cysiicercus fasciolaris [in this way], as the white mice 

 of my colony acquired such an appetite for flesh, from the day on which I began to 

 feed them with T. crassicollis, that they devoured each other, which was also observed 

 to be the case by Leuckart. 



With regard to the other species of cystic worms, all experimenters who are in a 

 position to determine the species of Tcenia and cystic worms will regard my state- 

 ments, confirmed by Haubner, Leuckart, Van Beneden, Eschricht, Roll, Moller, &c, as 

 correct, in opposition to those of Yon Siebold and May, and admit with me — 



1. That we can never rear all the known kinds of cystic worms infesting our domestic 

 mammalia from one species of Tcenia. 



2. That from the eggs of Tcenia serrata only Cysticercus pisiformis, from those of 

 T. solium only C. celluloses, from those of T. ex Cysticerco tenuicoUi only C. tenuicollis, 

 from those of T. crassicollis only C. fasciolaris, from those of T. Ccenurus only Ccenuri 

 are produced, and from those of T. crassiceps (Rud.) of the fox, according to Leuckart, 

 only C. longicollis ; and 



3. That each of these species can be developed only in a limited number of animals. 

 Thus hitherto we have succeeded in rearing the Cyst, cellulosce only in the pig after the 

 administration of T. solium; the Cyst, tenuicollis, horn Tea; cyst. tenuicoUi, only in 

 goats and sheep; the Ccenuri, from T. Ccenurus, only in sheep and cattle; and the 

 C. pisiformis, from T. serrata, only in rabbits ; whilst the brood of all these Tcenice, 

 when administered to other animals than those mentioned with the particular species, 

 always strayed, and soon died without becoming further developed in the unsuitable 

 dwelling-place. 



How important these experiments are in the determination of the species ofTaenial and 

 cystic worms, will be perceived at once by every one. They complete the attempts to 

 determine the species of Taenial and cystic worms according to their hooks, which, 

 however, is not so difficult as Von Siebold supposes. I appeal to the words of Pro- 

 fessor Roll, in an article ' On the result of the administration of the mature segments of 

 a species of Tape-worm (7". ectiiurus) of the Dog,' See., p. 11: "These three species 

 (7". coenurus, T. serrata vera, T. ex cystic. tenuicoUi,) of which I have received spe- 

 cimens from Dr. Kuchenmeister, may be easily distinguished from one another, both 

 from the form of their bodies in general, and also especially with reference to their cir- 

 clet of hooks, when they have once been carefully examined ; and Von Siebold therefore 

 appears to be in error when he states, in his very recent publication, ' Ueber die Band- 



