422 HISTORICAL ACCOUNT OF T^INIA SAGINATA. 



T. mediocanellata as a variety of the ordinary T. solium. Thus, 

 Weinland, among others, reports that in an American tape-worm, 

 which in size and structure of the head was exactly like Kiiehen- 

 meister's species, he found precisely the same form of uterus as in T. 

 solium. 1 He regards T. mediocanellata only as a common tape-worm, 

 which has by chance, or perhaps in consequence of a sudden wrench, 

 lost its rostellurn with the hooks, and had therefore, by continuous 

 use, gradually increased the size and strength of its suckers, the only 

 remaining organs of attachment. The large size and thickness of the 

 worm are consistent with such a supposition, since it is quite plausible 

 that these forms, presenting a large surface to be affected by the 

 pressure of the intestinal contents and the contraction of the in- 

 testinal wall, should therefore be most exposed to the danger of losing 

 their circlet of hooks; and the same factors which determine the 

 large size of the body, may possibly also be the causes of the abundant 

 branching of the uterus, for that represents after all only the space- 

 requirement of a great mass of eggs. 



All these suppositions and hypotheses were, however, dismissed 

 when I succeeded, some years after Kiichenmeister (1861), in rearing 

 the young form of Tcenia saginata* and establishing that the worm in 

 question differs in its development from Tcenia solium in a way as 

 characteristic as it is striking. While the latter, as we first knew 

 from Kiichenmeister, is in its youth the familiar bladder-worm of the 

 pig (Cysticercus cellulosce), the young T. saginata is found not in the 

 pig, but in the ox, as a hitherto unknown muscle bladder- worm, which 

 is from the first destitute of hooks and of a rostellum, and is other- 

 wise very different, especially in the size and structure of the rudi- 

 mentary head. 



By this demonstration, the question as to the nature and inde- 

 pendence of Tcenia saginata has been settled. To-day it is universally 

 recognised as a species distinct from Tcenia solium, a species, 

 moreover, which has a much wider distribution than the latter, 

 indeed occurring wherever the ox is a domestic animal, and where 

 its flesh is used as food. We find it in all countries, both in Temperate 

 and Torrid Zones, and know that in districts where it is the custom to 

 eat raw or almost raw flesh, as in Abyssinia, almost every one suffers 

 from it from their earliest years. Tcenia solium stands in the same 

 relation to the pig as T. saginata to the ox, but is less common, since 

 the breeding of swine is not so general as that of the ox, especially in 

 hot countries. 



1 "Essay on the Tape-worms of Man," p. 40: also, Med. Corrcspondcnzblatt des 

 wiirtemb. drzti. Vereins, p. 31, 1859. 



2 Oottingen Nackrichten, Nos. 1 and 2, 1862. 





