632 OCCURRENCE AND MEDICAL IMPORTANCE. 



Occurrence and Medical Importance. 



Davaine, " Traite" des Entozoaires," pp. 359-620, pp. 644-656. 

 Neisser, " Die Echinococcenkrankheit :" Berlin, 1877. 



Marie Prougeansky, " Ueber die multiloculare ulcerirende Echinococcusgeschwulst in 

 der Leber," Inaug.- Dissert., Zurich, 1873. 



Boecker, "Zur Statistik der Echinococcen," Inaug. -Dissert., Berlin, 1868. 



Among human parasites none can compare with the Echinococcus 

 in the variety of its occurrence. Even the Cysticercus cellulosce, which, 

 on account of its residence in such different organs, has been rightly 

 described as one of the most widely distributed helminths, is in this 

 respect far behind the Echinococcus. There is hardly an organ of the 

 human body in which it does not occasionally dwell even the bones 

 being occasionally infested by it. 



All these organs, however, do not contain the worm with equal 

 frequency. Like Cysticercus cellulosce, the Echinococcus has favourite 

 situations, and others which it visits less frequently, or perhaps only 

 rarely. The favourite seats of the two parasites are, however, very 

 different. The intermuscular connective tissue, for which the Cysti- 

 cercus has a special preference, is but rarely the seat of the Echinococcus. 

 In the brain, and especially in the eye, the Cysticercus is found far 

 more frequently than the Echinococcus; this in its turn has a special 

 preference for the viscera, which are avoided by the other, and above 

 all, for the liver. Neisser, who has given a very accurate and almost 

 complete account of the cases of Echinococcus hitherto observed in 

 man, and who has increased the 367 observations 1 of Davaine 

 (in 1860) to the large number of 986, mentions in his table no fewer 

 than 451 Echinococci in the liver, so that these almost amount to half 

 of all the cases recorded. After the liver in the scale of frequency, 

 we find the lungs and pleura with eighty-four distinct cases, the 

 kidney with eighty, the muscles and dermis (including the orbit) 

 with seventy-two, the brain with sixty-eight (spinal cord with only 

 thirteen), the female genitalia (including the mammae) with forty- 

 four (the male with only six), the true pelvis with thirty-six, the 

 circulatory apparatus with twenty-nine, the spleen and bones with 

 twenty-eight, the eye with three, and so on. Finsen, whose ob- 

 servations only extend over 255 patients, all of them Icelanders, 2 



1 Boecker, who only makes use of materials from the Berlin Hospital, reckons 

 altogether thirty-three cases. Of the earlier accounts, I mention particularly von 

 Liidersen, " Dissert, de hydatibus," Gottingen, 1808, and von Rendtorff, " De hydatidi- 

 bus in corpore humano repertis," Berolinae, 1822. 



2 " Bidrag til Kundskab om de i Island endemiske Echinococcer, " Ugeskr. for Lcegcr, 

 Bd. iii., p. 71, 1867. 



