LOESCHIA 



301 



Inside the cyst the nucleus breaks down and the chromatin and plastin are 

 distributed throughout the cytoplasm, in which they form secondary nuclei 

 of the protokaryon type, and finally some 75 to 100 young nucleated amoebae, 

 which apparently do not become flagellate, and so far as is known do not form 

 gametes, but this and. the further development require investigation. 



Metcalf has, however, observed zygosis in minute gametes of Amoeba 

 proteus. 



Genus Loeschia Chatton and Lalung-Bonnaire, 1912. 



Synonyms, ~ Amceba Ehrenberg, 1830, pro parte; Entamoeba 

 Casagrandi and Barbagallo, 1897; nec Endamceba Leidy, 1879. 



Definition. — Gymnamoebida, with a vesicular nucleus containing 

 a small karyosome (as a rule) and abundant peripheral chromatin, 

 and dividing by mesomitosis, and with cysts containing four to 

 eight nuclei, which form young amoebae which are not known to 

 be gametes. 



Nomenclature. — ^The name Amoeba was applied by St. Vincent 

 in 1822 and by Ehrenberg in 1830 to free living forms, of which 

 the type is Amceba proteus, which Poche thinks is the Volvox chaos 

 of Linnaeus; and the term Endamceba was given by Leidy in 1879 

 to the parasitic E. blattcB Biitschli, but this name cannot be applied 

 to the human parasites, because Mercier's researches have shown 

 that it may be different, and therefore it is necessary to use Chatton 

 and Lalung-Bonnaire 's term. 



Remarks. — ^The genus is composed of amoeba-like forms varying 

 i n size from 5 to 80 microns, and possessing distinct ectoplasm and 

 endoplasm, which, however, may be only visible during motion. 

 The ectoplasm is clear and hyaline, while the endoplasm may be 

 either "clear or finely granular. The nucleus usually has a karyo- 

 some and centriole. Reproduction is by simple division, schizogony, 

 and cyst formation. 



The species live in the alimentary canal of man and animals, 

 but may enter other tissues and organs, and may be pathogenic 

 or non -pathogenic . 



It is still doubtful whether artificial cultivation has been per- 

 formed successfully. 



Type Species. — ^The type species is Loeschia coli Loesch, 1875, 

 found in man, but used in the sense of the term as defined by 

 Schaudinn in 1903, and not as defined by Loesch in 1875. 



Classification. — Chatton and Lalung-Bonnaire suggested the 

 formation of two subgenera — viz., Loeschia, characterized by cysts 

 with eight nuclei, and Viereckia, distinguished by cysts with four 

 nuclei, but this has not been adopted so far. 



As there are a very large number of species described, we will 

 give a list classified according to the part of the body in which 

 they were discovered, but Schaudinn's statement made in 1903 

 should be remembered, ' The knowledge of the development is the 

 first postulate of protozoon research and because this knowledge is 

 lacking so^much^confusion exists. 



