29 



intestine of the cat, &c.), did not become developed 

 into jointed tapeworms, but bore behind the head a 

 long, inarticulated appendage, and died in a short time 

 without being further developed ; and that every spe- 

 cies only thrives in a particular species of animal." 



In the following year, Von Siebold repeated these 

 experiments, and in the main confirmed those of 

 Kiichenmeister ; differing from him, however, in his 

 last conclusion. 



I shall consider these parasites, therefore, not as a 

 separate group, but, as they are now understood to 

 be, the undeveloped or embryonic conditions of the 

 Teeniae ; and, as an example of these embryos, I shall 

 select the Cysticercus cellulosse. 



These Cysticerci (PI. II. fig. 6) appear as small, 

 elliptical, or rounded bladders, fibrous in structure, 

 and are contained in the tissue of the organ where 

 it has taken up its abode. This bladder or cyst (PI. 

 II. fig. 6, A) is resistant to the knife ; and when 

 opened it is found, that, by pressure, another vesicle 

 can be squeezed out. This vesicle contains an open- 

 ing, around which is adherent a third sac, which is of 

 globular, pyriform, or oval shape, semi-transparent, 

 of whitish color, with quite thin, fine, granular walls, 

 and but little resistant. These cysts in the C. cellu- 

 losse present a long diameter of 15 to 20 mil. and a 

 short one of from 5 to 6 mil. Within the cyst is 

 contained the scolex, as it were, doubled upon itself; 

 i.e., the head and neck retracted upon itself. When 

 in this position, its site upon the outside sac is marked 

 by a little umbilicated depression surrounded by a 



