CLASSIFICATION AND NOMENCLATURE. 31 



dent that the authors were dealing with mixed in- 

 fections with both harmless and pathogenic amoebae. 

 In addition, the names given to the first two species 

 cannot stand, as they are not in accordance with the 

 binominal system adopted in nomenclature. 



In 1894 Kruse and Pasquale distinguished four 

 varieties of amoebae based entirely upon morphological 

 characteristics: (1) a form presenting a very re- 

 fractive protoplasm, found in normal feces; (2) a 

 form showing irregular and small granules; (3) a 

 form in which the endoplasm consisted largely of 

 vacuoles; (4) a form in which the protoplasm was 

 filled with foreign bodies. The two latter forms 

 were found only in dysenteric feces. 



It will at once be seen that the differences in these 

 forms are so slight as to be of no scientific value as 

 a basis of classification, and the fact that these 

 authors described the form found in normal feces as 

 being very refractive, is evidence that they confused 

 the pathogenic and harmless species, although they 

 recognized a pathogenic amoeba, Amoeba dy sentence, 

 following Councilman and Lafleur who, in 1891, ob- 

 jected to Amoeba coli, as a name for the amoeba 

 causing dysentery, and suggested the name "Amoeba 

 dysenteric? " The latter authors, while not attempt- 

 ing to differentiate species, expressed it as their 

 opinion that under certain conditions both harmless 



