236 



THE ANIMAL PARASITES OF MAN 



sheep, 1 the stag, dog, cat, brown bear and monkey, as well as 

 in man. The cysticercus of the pig is an elliptical vesicle with a 

 longitudinal diameter of 6 20 mm., and a transverse diameter of 

 5 TO mm. 



Even with the naked eye. a white spot may be observed in the 

 centre of the long equator, this being the invaginated head ; it is 

 easy to make it project by pressing on the vesicle, and on examin- 

 ing it under the microscope one can convince oneself that it 

 corresponds with the head of Tcenia solium. 



FIG. 163. Large and small hooks of Tcenia solium, 280/1. 

 (After Leuckart). 



a b 



FIG. 165. Two 



FIG. 164. (a] Ovum of Tcsnia solium yiith fully-developed mature proglottides 

 embryo ; the residue of the vitellus within the egg-shell. of T, solium with 

 (b) Isolated embryo of T. solium within the embryonal shell. fully developed 

 450/1. uterus. 2/1. 



Numerous experiments have proved that the Cysticercus cellu- 

 lose of the pig, if introduced into the intestine of man, grows to a 

 Tcenia solium (Kuchenmeister 1855, Humbert 1856, Leuckart 1856, 

 Hollenbach 1859, Heller 1876) ; the cysticercus has frequently also 

 been cultivated purposely by feeding pigs with mature proglot- 

 tides of Tcenia solium. (P. J. van Beneden 1853, Haubner and 

 Kiichenmeister 185 5 ^Leuckart 1856, Hosier 1865, Gerlach 1870, 

 &c.) ; but success did not attend the efforts to make Cysticercus 

 cellulosce settle in the intestine of pigs, dogs, guinea-pigs, rabbits 



1 The cysticerci, which on rare occasions are found in the muscular system of 

 sheep, are either strayed specimens of Cysticercus tenuicollis, which normally develop in 

 organs of the abdominal cavity, and appertain to Tcenia marginata of the dog, or 

 Cysticercus cellulosce. (Compare "Bongert, in Zeitschr. /. Fleisch u. Milchliyg., 1899, ix., 

 p. 86.) 



