144 
Entamoeba histolytica 
2. The effects of the substances chlorine, tyrosin, and skatol on culture 
amoebae have been investigated; it has been found that the two first sub¬ 
stances stimulate vegetative reproduction, but that skatol induces cyst 
formation. 
3. The changes that the nucleus undergoes preparatory to division and 
the behaviour of the karyosome during division are fully described. It is 
shown that the nuclei originally described as characteristic of E. histolytica 
and E. tetragena are phases of nuclear change in the life history of the same 
animal. 
4. Cyst formation and the nuclear divisions in the cysts are described, 
together with a short discussion as to the view taken that the chromatoid 
bodies are not comparable with the chromidia of other Rhizopoda. 
5. Reasons are adduced for the suggestion that during the further deve¬ 
lopment of the cysts quadrinucleate amoebae emerge, which divide to form 
four small amoebulae. 
6. Degeneration in E. histolytica is described and the view of Darling, 
that budding phenomena are degenerative ones, is confirmed. 
REFERENCES. 
The references are given in brief, at the Editor’s request, to save labour in printing 
"titles of papers already cited in full in lists of references given by other authors in Parasitology, 
will be found at the places indicated by “see ref.” 
Bartlett, G. B. (1917). Quart. Journ. Medicine, x. 
Collin, B. (1913). See ref. Arch.'f. Protistenk. xxxiv. 185. 
Cropper, J. W. and Drew, A. H. (1914). Researches into Induced Cell-Reproduction in 
Amoebae. London. 
Craig, C. F. (1908, 1913). Journ. Infect. Diseases, v., xm. 
Cutler, D. W. (1917, 1918). Journ. Path, and Bad. xxi., xxii. 
Dale, H. H. and Dobell, C. (1917). Journ. Pharm. and Exp. Therap. x. 
Darling, S. T. See ref. Arch. f. Protistenk. xxxiv. 185. 
Dobell, C. (1909). See ref. Parasitol. x. 310. 
- (1914). Arch. f. Protistenk. xxxiv. 
- (1918). Parasitol. x. 
Dobell, C. and Jepps, M. (1917). See ref. Ibid. 310. 
- (1918). Ibid. 320. 
Doflein, F. (1911). Lehrbuch der Protozoenkunde. Jena. 
Elmassian, M. (1909). See ref. Arch. f. Protistenk. xxxiv. 186. 
Fantham, B. (1911). Ann. Trop. Med. and Parasitol. (Liverpool), iv. 
Greenwood, M. (1894). Phil. Trans. (B), clxxxv. 335. 
Hartmann, M. See ref. Arch. f. Protistenk. xxxiv. 186. 
Hertwig, R. (1898). Abhandl. bayer. Akad. xix. 
James, W. M. (1915). Ann. Trop. Med. and Parasitol. vm. 
Job, E. and Hirtzmann, L. (1916). G. R. Soc. Biol, lxxiv. 
Kuenen and Swellengrebel (1913). Centralbl. Bakt. (Orig.), lxxi. 
Mathis, C. and Mercier, L. (1916 and 1917). See ref. Parasitol. x. 350. 
Mercier, L. (1910). Arch.f. Protistenk. xx. 143. 
Mtnchin, E. A. (1912). An Introduction to the Study of Protozoa. London. 
