DR. THEODOR NEUMANN. 221 



one host, it is easily to be understood that the latter will 

 suffer severe damage ; less perhaps through the loss of 

 blood than through the constant irritation and inflam- 

 mation of the mucous membrane. These Strongylids are 

 the more interesting since one of their representatives 

 belongs to the most dangerous parasites of man, and has 

 done much harm through its presence. This worm has 

 the name Ankylostoma duodenale or Dochmius duode- 

 nalis. It lives, and mostly in large numbers, in the upper 

 part of the small intestine, the duodenum, from which it 

 has its name, and it produces through its parasitism the 

 symptoms of a highly dangerous anaemia which was a 

 long time known under the name of Egyptian chlorosis. 

 Later a similar disease was discovered among country 

 people of Sicily who came from swampy territories, and 

 in the northern parts of Italy, especially among people 

 who work in rice-fields and in brick-factories. During 

 the construction of the St. Gothard tunnel the very 

 same suffering spread rapidly among the laborers em- 

 ployed in this work; it was called "tunnel disease," 

 '*mine anemia," "mountain cachexy," etc. There, 

 for the first time, the worm was discovered as the cause 

 of the disease; it was found in all the patients, and later 

 more searching investigation proved the fact that it 

 caused the same disease among the coal miners of Bel- 

 gium and on the Rhine. This ankylostomiasis (or doch- 

 miosis) is a rather dangerous disease which may extend 

 through many years and finally lead to death. The parasite 

 itself is indeed not very large (8 to 11=""), but through 

 the constant irritation which it exerts by means of its 

 horny armament around the mouth, and through the loss 

 of blood which it causes, it takes few individuals to pro- 

 duce the most serious results. How much worse must 

 the effects be if hundreds, nay, thousands of individuals 

 inhabit the alimentary canal of one individual! More- 

 over, it is very hard to drive these parasites off; even 



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