314 THE ANIMAL PARASITES OF MAN 



particularly frequent in East Prussia amongst the inhabitants of 

 the Courland Lagoon district, on the Baltic ; it is, moreover, also 

 found in the Province and even in the City of Konigsberg. In West 

 Prussia and Pomerania it is very much scarcer. 



It is also found in Munich and in the vicinity of the Lake of 

 Starnberg (Bollinger). 



Krabbe found it in 10 per cent, of the sufferers from tape- 

 worms in Denmark; Szydlowski found the ova of this worm in 

 Dorpat in 10 per cent, of the faeces examined; Kruse found the 

 worm in 6 per cent, of post-mortems ; Kessler, in Petrograd, 

 found the eggs in the faeces in 7-8 per cent. ; at post-mortems he 

 found the worms in 1*17 per cent., though Winogradoff only found 

 it in 0*8 per cent. In Moscow, according to Baranovsky, 8'9 

 per cent, of the faeces examined contained the ova of Dibothrio- 

 cephalus. In the interior and southern provinces of Sweden the 

 worm, according to Lonnberg, is only found sporadically, but, on 

 the other hand, in Angermanland about TO per cent, of the popula- 

 tion is affected ; while again in Norbotten the majority of persons 

 are affected, and in Haparanda the entire population (with the 

 exception of infants) harbour this parasite. In Switzerland 

 D. latus is very frequent in close proximity to the lakes of Bieler, 

 Neuchatel, Morat and Geneva (according to Zaeslin 10 to 15 to 

 20 per cent, of the population are affected) ; the parasite is less 

 frequent in districts one to four hours removed from these lakes. 



Of the fish from Swiss lakes examined by Schor those from 

 Lake Geneva were most commonly infected, and especially Lota sp. 

 and Perca sp. 



The frequency and distribution have, nevertheless, decreased 

 perceptibly in places; at the. commencement of the eighteenth 

 century the broad tapeworm was very common in Paris, at the 

 present date it only occurs when imported (Blanchard) ; in 

 Geneva, also, according to Zschokke, it has become rarer (formerly 

 10 per cent., now only i per cent.). 



The disturbances produced in man by the presence of broad 

 tapeworms are, as a rule, very trifling ; in other cases they produce 

 partly gastric disorders and partly nervous symptoms ; in a number 

 of cases, again, they set up severe anaemia, apparently caused by 

 toxins produced by the worms and absorbed by the host. There 

 is no danger of auto-infection, as the larval stage lives only in 

 fishes, not in warm-blooded animals. The case reported by 

 Meschede (ova like those of Dibothriocephalus latus in the brain of 

 a man who had suffered from epilepsy for six years) must be otherwise 

 explained. 



Human beings, like other hosts, can only acquire the broad 



