34 



THE ANIMAL PARASITES OF MAN 



canal of man. 1 The corresponding cysticerus is Cysticercus bovis, and 

 is found almost exclusively in the ox ; it is small, 7-5 to 9 mm. 

 in length and 5-5 mm. in breadth, may easily escape notice, and 

 requires from three to six months for its development. Numerous 

 experiments have confirmed the connection of Cysticercus bovis with 

 Tcenia saginata ; indeed, the Cysticercus was only discovered by feeding 

 experiments after attention had been called to the ox as the probable 

 intermediary host of thisTaenia. 



Medical men observed that weakly children who were ordered to eat raw scraped 

 beef to strengthen them contracted T. saginata. It was found, moreover, that 

 Jews, who are prohibited from eating pork from religious motives, suffered especially 

 from 71 saginata; when T. solium was found to occur in a Jew he often con- 

 fessed to having eaten pork ; and finally it was found that certain nations for 

 instance, the Abyssinians frequently harbour 71 saginata, and only eat beef raw 

 by preference. 



These observations led Leuckart, in 1861, to feed 

 young calves with the proglottids of T. saginata in 

 order to discover the corresponding Cysticercus, which 

 was then not known. This experiment was successful. 

 Similar experiments, with similar results, were then con- 

 ducted by Mosler (1863), Cobbold and Simonds (1864 

 and 1872), Roll (1865), Gerlach (1870), Ziirn (1872), 

 Saint Cyr, Jolicceur (1873), Masse and Pourquier 

 (1876), and Perroncito, in 1876. The attempts to 

 infect goats, sheep, dogs, pigs, rabbits and monkeys 

 were unsuccessful. Only Zenker and Heller were able 

 to infect kids, and Heller infected one sheep, but these 

 are exceptions. 



Artificial infections of human beings with 

 Cysticercus bovis to obtain the tapeworm were 

 less numerous, and indeed quite superfluous, 

 yet this was also done by Oliver (1869) in India, 

 and Perroncito (1877) in Italy. The experi- 

 ments of the latter prove that the extracted 

 cysticerci of the ox certainly perish in water at 

 47 to 48 C. 



FIG. 244. A piece of 

 the muscle of the ox, with 

 three specimens of Cysticer- 

 cus bovis. Natural size. 

 (After Ostertag.) 



It is a remarkable circumstance that, at least as 

 regards Central Europe, C. bovis in the ox, after natural 

 infection, was so seldom found that almost every case 



was published as a rarity ; whereas the Tasnia is very frequent in man. The 

 reason for this is that in Germany cattle are not severely infected, and that the 

 small, easily dried-up cysticerci easily escape notice in the large body of the host. 

 Hertwig, the late director of the town cattle market in Berlin, in 1888, pointed out 



1 Abnormal migrations of this species have also been known. Compare, amongst 

 others, Stieda, A., " Durchbohr. d. Duod. u. d. Pancreas durch eine Tsenia," Centralbl. 

 f. Bakt., Path, tmd Infektionsk., 1900, xxviii (i), p. 430. 



