36 THE ANIMAL PARASITES OF MAN 



a small species (0-025 mm.), finely granular, the Amoeba coli, Losch, which 

 is pathogenetic to man and the cat ; a larger one (0*040 mm.), coarsely 

 granular, the Amoeba coli mitis, which is pathogenetic to man but not 

 to the cat ; and a species of similar appearance, the Amoeba intestini 

 vulgaris, which is innocuous both to man and cat. Celli and Fiocca 1 even 

 go a step further, differentiating, as they do, the following species in the 

 intestine of man : (i) Amoeba lobosa, with var. guttula (i.e., Amoeba guttula, 

 Duj.), var. oblonga (i.e., A. oblonga, Schm.), and var. coli (i.e., A. coli, 

 Losch); (2) Amoeba spinosa, n. sp. (in the vagina as well as in the intestine 

 of persons suffering from diarrhoea and dysentery) ; (3) Amoeba diaphana, 

 n. sp. (in the human intestine in cases of dysentery) ; (4) Amoeba vermi- 

 cularis, Weisse (in the vagina and in the intestine in dysentery) ; and (5) 

 Amoeba reticularis, n. sp. (in the intestine in dysentery). These authors state 

 that they have also found all these species free in the soil or in the 

 ooze of waters, and have cultivated them in pure cultures. It is, however, 

 probable that in all these experiments it was not a question of exclusively 

 animal organisms, as the existence of the latter depends on food very 

 different to that which was used in the pure cultures" ; it is therefore 

 advisable to take up an expectant standpoint in this connection. 



Of the species differentiated by Quincke and Roos, two (A. intestini 

 vulgaris and A. coli mitis) may be regarded as identical, because no morpho- 

 logical differences have been described, and because the statement that 

 their effect on man is different is, to say the least, doubtful. 5 It is there- 

 fore reasonable to infer that two species were under discussion, one patho- 

 genic and the other harmless. The possibility of a morphological difference 

 between the two forms has, however, not hitherto been proved, and has 

 recently been again denied, notably by Roemer (1898). In spite of the 

 numerous works published within recent years on the intestinal amoebae of 

 man, no definite conclusion has yet been arrived at. Notwithstanding this, 

 at the present time medical men strictly differentiate bacillary dysentery from 

 amoebic dysentery or amoebic enteritis ; the former occurs in Germany in 

 the dysentery district (Kruse, 1900, 1901), the latter particularly in East 

 Prussia (Jaeger, 4 1902). 



1 Celli, A., and R. Fiocca, " Beitr. z. Amcebenforsch, II." (C. /. B. u. P., 1894, xvi., 

 p. 329); " Ric. int. alia biol. d. Amcebe " (Bull. Accad. med. Roma, 1894-95, xxi.. 

 p. 285) ; Ref. in C. f. B., P. u. I., 1897, xxi., p. 290. 



2 It is quite different with the experiments of Frosch (C. /. B., P. u. /., 1897, P- 

 926) ; Tsujitani (ibid., xxiv., p. 666); and Schardinger (Stzgsb. d. K. Acad. d. Wiss. 

 Wien. Math.-mt. Cl., 1899, cviii., part i, p. 713), who fed their nurslings with suitable 

 bacteria : they do not, however, concern us here, being free-living species. 



3 Compare also Quincke, " Ueb. Protozocn-Enteritis " (Berl. klin. Wchschr., 

 1894, Nos. 46 and 47). 



4 Jaeger, H., in C. f. B., P. u. I., xxxi., Orig., p. 551. 



