AMCEBINA 21 



nucleus, is known as Amoeba diploidea ; l while the second variety 

 has one nucleus only, and is apparently related to A. Umax. 2 



A good deal of information may be gained from the study of 

 A. blattce, which is found in the terminal portion of the intestinal canal 

 of cockroaches. This organism belongs to yet another group of 

 Amoebae and is particularly instructive on account of the very distinct 

 " streaming " movements of the plasm. It should be sought in freshly 

 caught beetles only, as after the beetle has been in captivity for two 

 or three days the organisms disappear from the intestine. The head 

 and hinder part of the body should be cut off, and the intestine may 

 then be withdrawn with the tweezers from the hinder orifice. 



Material for the examination of the dysentery Amoebae of man is 

 sometimes difficult to procure. The species most frequently met with 

 is E. tetragena which is frequently found in people returning from 

 hot climates. 



(1) E. tetragena has only quite recently been isolated from 

 E. histolytica. It is found in Africa and South America, and is 

 recognized by the fourfold nucleation of its cysts. In its method 

 of development it closely resembles the E. coli, but differs from it 

 not only in the fourfold nucleation of the adult cysts, but also in 

 possessing during the resting stage a homogeneous and highly refrac- 

 tive ectoplasm. In this latter property it resembles E. buccalis and 

 E. histolytica. The ectoplasm is easily distinguished from the endo- 

 plasm, which has generally a lower refractive index and contains 

 nuclei, vacuoles, food remnants, &c. The nucleus is very charac- 

 teristic and quite different from that of the other bowel Amoebae of 

 man. Like the nucleus of E. coli, it is round in shape, contains 

 a somewhat large amount of chromatin, and has a central caryosome, 

 which may be large or small. When carefully stained, this caryosome 

 shows a central spot which Hartmann 3 compares to the centriole in 

 the centrosome of Metazoa. " Sometimes this centriole occupies the 

 whole of the centre of the nucleus. In that case it is surrounded by 

 a clear space, while the original margin of the caryosome persists 

 as a sort of membrane." Reproduction during the inactive stage has 

 been observed only in the form of fission. This species, which is not 

 seen in man except in cases of dysentery, may be transferred to the 

 cat, where it approximates very closely to E. histolytica. 



1 M. Hartmann and K. Nagler, "Copulation bei Amoeba diploidea n. sp. mit 

 Selbstandigbleiben der Gametenkerne wahrend des ganzen Lebenscyclus," Sitzber. 

 Ges. naturf. Frde., Berlin, 1908, No. 5, pp. 112-125. 



2 M. Hartmann and S. Prowazek, " Blepharoblast, Caryosom u. Centrosom." 

 Arch. f. Protistenkunde, vol. x, 1907, pp. 314-315, fig. 4 f . 



3 M. Hartmann, " Eine neue Dysenterieamobe, Entamosba tetragena (Viereck), 

 syn. Entamoeba africana (Hartmann)," Beihefte z. Arch. f. Schiffs- u. Tropenhyg., 

 1908, Bern. 5 (Verhandlg. d. deutsch. tropenmed. Ges. I.), pp. 117-127, fig. 9. 



