CHAPTER XX 



THE CULTIVATION OF ENDAMCEBA HISTOLYTICA 



By 



Charles F. Craig 



Medical Corps, United States Army 



Since the discovery of Endauiocba histolytica by Loesch, in 1875, 

 many investigators have claimed to have been successful in cul- 

 tivating this parasite but it is only recently that success has been 

 achieved in this direction. Until 19 18, it is safe to say that the 

 cultures of amoebae obtained from human feces and supposed to be 

 those of E. histolytica were really those of free-living species 

 which were confused with the parasitic amoebae of man and other 

 animals. This mistake was made by Kartulis (1890), Musgrave 

 and Clegg (1904), Walker (1908), Williams (1911) and many 

 others, and it is now generally admitted that none of the amoebae 

 cultivated by these observers were E. Jiistolytica but were free- 

 living amoebae that had contaminated the material cultured or the 

 culture media. It was not until W^alker, in 191 1, as the result of a 

 careful study of cultural amoebae, had proven them all to be free- 

 living species and that it was impossible, with the methods then 

 available, to cultivate E. histolytica, that it was generally recog- 

 nized that these cultural amoebae had nothing in common with 

 E. Jiistolytica, or other parasitic amoebae, and that none of the 

 latter had been cultivated. 



Walker's work confirmed that of the writer, in this respect, 

 and it may be stated with truth that all of the reports of the suc- 

 cessful cultivation of E. Jiistolytica prior to 19 18 are inaccurate, 

 being based upon erroneous observations and that the amoebae cul- 

 tivated prior to that time were, in all probability, free-living species 

 belonging to the genera Amoeba, VaJilJzampfia, or Hartnianella. 



In 1918, Cutler claimed to have cultivated E. histolytica upon 

 a blood-clot medium and upon an tgg medium. The cultures were 



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