238 ANIMAL PARASITES. 



2. To give instructions that the vesicles in question, wherever 

 they may be evacuated, either artificially or naturally, should be 

 burnt, but never to allow them to be thrown upon dung-heaps, 

 or places where they can be got at by the dogs. 



As soon as the dogs have developed the Taenia Echinoc. altri- 

 cipariens to maturity in their interior, they escape externally 

 with the dung, and get into the water, and also on the 

 pastures and vegetables, as we have already often seen. In 

 Iceland, also, the following circumstances may concur. Not 

 only the humidity of the soil ki the districts in which the 

 Echinococci are endemic, of which we have already spoken, but 

 the warm temperature, remaining the same summer and winter, 

 of much of the running water 1 which is used for drinking, 

 caused by the entrance of the numerous hot wells into the water, 

 may, perhaps, not be entirely without influence, as the luke- 

 warm temperature appears to agree particularly well with all the 

 lower animals, and therefore, probably, also with the cestode 

 embryos in question. For the rest, the mode of life of the 

 Icelanders affords the following peculiarities which may, possibly, 

 be regarded as the principal causes of the communication of the 

 infection of the eggs of Tasniae. 



Possibility of infection by drink. In Iceland there are six 

 kinds of drinkable natural waters made use of. 



1. Glacier- water, a water which reaches the valleys in a 

 milky state, and is only drunk in case of need. 



2. Rain-, and 3, brook-water, which do not come from 

 glaciers, and are very fresh and wholesome. 



4. Spring-water, which is still more frequently used, and is 

 considered as very wholesome, but generally has a styptic action 

 upon the intestinal evacuations. 



5. A very cold water proceeding from springs which never 

 freeze, and 



6. Cooled thermal waters, when these have not too mawkish 

 a taste. 



It is evident that the waters mentioned under 2, 3, and 4, 

 and perhaps 5, may be especially the agents in the transport 

 of the eggs of the Tanice into the human intestines. The 



pylorus and at the passage of the small intestine into the colon, and send it, in spirits, 

 to its address. The stomach and rectum are unnecessary for this investigation. 



' I may refer, for example, to the River Reykedal, which, in spite of its warmth, is 

 overstocked with extremely fat trout and salmon. 



