STRUCTURE OF THE PROGLOTTIDES. 



423 



Growth and Structure of Tcenia saginata. 



Sommer ' ' Ueber den Bau uud Entwiokelung der Geschlechtsorgane der'Tsenia medio- 

 cxaeHsAa," Zdtschr. f. wiss. Zool., Bd. xxiv., p. 499, 1874. 



The designation " grandis saginata" which Goze has given to this 

 species, in contrast to the one which we now call Tcenia solium (his 

 "plana pellucida "), gives at once an idea of the characteristic 

 size and appearance of the worm. It is natural, then, that the 

 characters expressed by these words should be first used for specific 

 diagnosis. 



We must not forget, however, that these peculiarities are not 

 always equally conspicuous. We find specimens, for instance, which, 

 though perhaps of the normal length, have by no means the charac- 

 teristic appearance, being far thinner and almost transparent, so that 

 they might be readily referred to Tcenia solium, were it not for the 

 absence of hooks on the head, and the frequent ramification of the 

 uterus. 



As a rule the physician has not in his diagnosis to deal with the 

 whole worm, but only with the isolated proglottides. The identifi- 

 cation of the latter is a matter of great importance, since the Tcenia 

 saginata is very different from T. solium, both in its pathological and 

 therapeutic aspects. For the latter involves much greater danger to 

 the patient, for reasons which will presently appear, and is therefore 

 to be removed as expeditiously as possible, while T. saginata admits 

 of a more temporising mode of treatment, which is the more fortunate 

 since the worm in question, though bookless, has a considerable power 

 of resistance, and is only to be dislodged by very powerful and 

 energetic means. 



Fig. 240. — Isolated proglottides of 7'cenia saginata (nat. size). 



The Proglottides. — It is of some aid in diagnosis to note that the 



proglottides of T. saginata are by no means so exclusively expelled in 



the stools as those of T. solium ; in great part, indeed, they leave the 



host spontaneously, which is very rarely the case with the latter. 

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