that just iu this district every third adult person is said to 

 have hydatids. AVhether this is exact or not I cannot tell, but 

 thus it was stated to me by a physician who has been serving 

 there for more than thirty years." So much for the preva- 

 lence of hydatids in the chief domestic herbivora of that 

 country ; and now let us turn our attention to the dogs of Ice- 

 land. Krabbe examined 100 Icelandic dogs, and found that in 

 28 of these Taenia Echinococcus was present, often in vast 

 numbers. In Copenhagen he examined 500 dogs, but found 

 this worm present in only two instances. Thus Taenia Echino- 

 coccus is seventy times as common in Icelandic dogs as in those 

 of Copenhagen, According to Cobbold, who is the first 

 authority on helminthology in G-reat Britain, Taenia Echino- 

 coccus has never been found present in any English dogs which 

 had not previously been fed experimentally upon hydatids. 

 This quite corresponds with the comparatively rare occurrence 

 of hydatid disease in England. Then it must be remembered 

 that in a country where sheep are so numerous, the dogs enjoy 

 innumerable opportunities of eating the livers and lungs of 

 sheep affected with Echinococcus, and thus they come to harbour 

 vast numbers of the little tapeworms. And now as regards 

 the last link in the chain of causation of hydatids, viz., the 

 swallowing by man of the eggs of the tapeworms. All travellers 

 whose works on Iceland I have read draw special and fre- 

 quent attention to the gross uncleanliness of the people. 

 Sheep, cows, and dogs live under the same roof as the family 

 during the long weary months of Iceland's bitter winter. The 

 houses are devoid of ventilation, and almost entirely of light. 

 The configuration of the country is such that extensive bogs 

 and swamps alternate with lofty mountains, large rivers, and 

 numerous lakes of all dimensions. The bogs and swamps are 

 just the most suitable receptacles for the eggs of the tapeworm, 

 deposited in myriads on the long matted grass, or more solid 

 hummocks that often stud the area of the swamps. Then, 

 owing to the diet of the people being largely composed of 

 stock-fish, scurvy is common, and raw vegetables are a delicacy 

 and greedily consumed, thus giving another agent for the con- 

 veyance of the ova into the body. No doubt the three chief 

 media are the bog and swamp-water used for drinking pur- 

 poses ; the consumption of raw vegetables, upon which the 

 eggs have been deposited ; and the habit of allowing dogs 

 to cleanse the plates by licking them. Even the stock-fish that 

 constitutes the staple article of diet is heedlessly piled on 

 the filthy floor of the dwelling-house, ready to become befouled 

 by the dogs. The ])revalence of the disease among the sheep is 

 explicable in like manner by the swamp-water drunk, and the 

 grass eaten by them. " The only land cultivated in Iceland is 



