STRUCTURE AND DEVELOPMENT OF ECHINOCOCCUS 



355 



oxen, 27-1 per cent, sheep, and I2'8 per cent, pigs are infected ; in Greifswald, indeed, 

 64-58 per cent, oxen, 5TO2 per cent, sheep, but only 4-93 per cent, pigs are infected. 

 In accordance with these figures Tccnia echinococcus must be frequent in dogs in 

 Ponierania, especially in Upper Pomerania ; on the other hand, the conjecture that 

 the frequency of echinococcus in Mecklenburg is explained by the occurrence of 

 Tcenia echinococcus in foxes has not been confirmed, as the fox does not harbour this 

 worm in Mecklenburg. 



Beyond the European continent, echinococcus is frequent in 

 the inhabitants of Iceland, Argentine, Paraguay and Australia. In 

 Iceland, according to Finsen, i in every 43 inhabitants is affected 

 with echinococcus ; according to Jonassen the proportion is I to 63 ; 

 this is clue to the habits of the people of Iceland or, in fact, 

 to the frequency of Tania eclii no- 

 coccus in dogs, and the prevalence 

 of the hydatid in cattle. In cer- 

 tain districts of Australia it is 

 just as frequent. In Cape Colony, 

 Egypt and Algeria echinococcus 

 is not rare, but it is scarce in 

 America and in Asia, with the 

 exception of the nomadic tribes 

 of Lake Baikal. 



Echinococcus attacks persons 

 of every age, though it is rare in 

 children up to 10 years of age 

 and in old people. It occurs 

 most frequently between the ages 

 of 21 and 40 years. According 

 to all statistics it preponderates 

 in women (about two-thirds of the 



The liver is its favourite 



FIG. 258. Hooklets of echinococcus. a, of 

 Echinococcus veterinorum ; If, of 7^cenia echino- 

 coccus, three weeks after infection ; c, of the 



per Cent. Of the Cases) adult Tania echinococcus', d, the three forms 



of booklets outlined one within the other. 



600/1. (After Leuckart.) 



cases). 



seat (57* i 



next in order come the lungs 



(8 per cent.), kidneys (6 per cent.), 



cranial cavity, genitalia, organs of circulation, spleen (3-8 per cent.), etc. 



As a rule one organ only is invaded ; multiple occurrence may originate 



from one infection, or eventually from a later infection (?), or it may 



come to pass that from some cause (through the spontaneous rupture of 



an echinococcus, or the rupture of one caused by an injury or surgical 



operation) daughter cysts, brood capsules or scolices escape into the 



abdominal cavity, 1 where they settle or become transformed and go 



1 In such cases the toxic effects of the echinococcus fluid usually if not always manifest 

 themselves. Such effects are manifested by severe symptoms of poisoning being set up, by 

 urticaria, peritonitis, and ascites, and not infrequently they cause a fatal termination. 



