236 ANIMAL PAEASITES. 



to devour their masters. Even here the proof lies more at hand 

 than we should perhaps have supposed. It is a well-known fact, 

 as already observed, that colonies of Echinococcus evacuate their 

 daughter- and granddaughter-vesicles with the fseces, by vomiting 

 and coughing, and with the urine, or that these vesicles are set 

 free by the incision or opening of such Echinococcus-cysts by the 

 trocar or knife of the surgeon. Hitherto, no doubt, these vesicles 

 have been too inconsiderately dealt with, they have been 

 allowed to lie just where they fell, as, for instance, with the 

 faeces, 1 or the vesicles removed Ify the trocar have been thrown 

 upon the open dung-heaps. As a matter of course dogs can 

 easily get at all these places, and, especially in the half-wild 

 state in which these animals live in Iceland, they will greedily 

 fall upon and devour these vesicles upon the dung-heaps, or those 

 evacuated in the immediate neighbourhood of the patient by 

 coughing, vomiting, or with the urine, and thus easily infect 

 themselves with immense numbers of T&nia Echinococcus altrici- 

 pariens, if these vesicles, as is frequently the case, are passed 

 uninjured. In order to give a further support to this hypothesis 

 of the passage of the vesicles into the intestine of the dog, we 

 must certainly first of all consider the question whether so many 

 free dogs do really occur in Iceland, that they may easily get at 

 these evacuated vesicles. All travellers agree as to the number 

 of dogs possessed by the Icelanders, and I borrow the following 

 remarks partly from the works already referred to and partly 

 from the travels of Olavius. 



The Icelanders in all districts keep the following three kinds 

 of dogs in considerable numbers. 



]. The sheep- or cattle-dogs (Faar houndar), of which there 

 are two sub-varieties. The smaller of these two races has long 

 hair, short and weak legs, a pointed snout, and a curly tail ; 

 the other has curly and coarse hair. The Icelanders employ 

 them in seeking for lost animals ; as the sheep, as well as cows 

 and horses, in Iceland, usually seek their food for themselves, 

 often without herdsmen, the whole year round, and thus, of 

 course, may readily stray upon the pastures and in the rnoun- 



1 I find no account, in the descriptions of travels, of the Icelanders making use of 

 closed privies ; everywhere nothing but open dung-heaps are spoken of. Besides, the 

 Icelander may also deposit his dung in the open air, just when the necessity comes upon 

 him, and indeed it cannot be otherwise with fishermen and shepherds. 



