CESTODES. 



271 



pendent animals, 1 but the so-called head can, after the loss of its 

 chain of joints, grow again to a new tape- worm within a few weeks. 

 Can we wonder that these observations long ago raised a doubt as to 

 the correctness of the usually accepted theory, and that thoughtful 



FIG. 131. 



FIG. 132. 



Fio. 131. Tape- worm form of Tcenia sayi- 

 nata s. mediocanettata. 



FIG. 132. Isolated Proglottides of the same. 



investigators more than a century ago suggested that the tape-worm 

 was no simple individual, but a compound animal. 



Not to speak of the Arabian physicians, this was the opinion of 

 Vallisnieri 2 and Coulet, 8 and also of Linne, who places the tape- worm 



1 In fact, these discharged joints, especially of Twnia saginata, have been repeatedly 

 considered both in ancient and modern times as distinct parasites, Verities atcurbitini. 



2 " Considerazioni ed esperienze intorno alia generazione dei vermi del corpo umano," 

 p. 75 : Padova, 1710. 



a " Tractatus de ascaridibus et lumbrico lato," p. 37, &c. : Lugd. Bat., 1729. 



